‘Eye-Like Radiance’: The Depiction of Gemstones in Roman Wall Painting

: The study of ornament in Greek and Roman art has been the focus of increasing scholarly interest over the last decade, with many publications shedding new light on the dynamics of ornatus in antiquity, and the discourses that shaped and situated it. Through an analysis of the depiction of gemstones in Roman wall painting, this article demonstrates the importance of ornamental details both to the mechanics of two-dimensional representation and to the interpretation of the images they adorned. I argue that by evoking the material qualities and sensual pleasures of real precious stones, painted gems served on the one hand to enhance the illusory reality of wall painting, and on the other to extol the delights of luxury and reﬁnement—that is, of ornamentation itself.


Introduction
Scholarship on Roman wall painting has traditionally privileged the figurative over the decorative. This has often been motivated by a desire to recover the appearance of lost Greek panel paintings, but even studies that have stressed the aesthetic and metapoetic sophistication of Roman frescoes on their own terms, and that have demonstrated their importance as a means of displaying wealth and social status within the Roman house, have focused for the most part on depictions of mythological narratives-or else on illusionistic architectural vistas-isolating both from the painted decorative details that accompanied their representation. 1 If ornament has been considered in these studies, it has more often been seen as a tool for stylistic analysis and dating than given representational agency of its own (Squire 2018, p. 21).
It is clear from the ancient texts, however, that Roman viewers of painted frescoes did not separate figure from decoration-or work from frame-in the way that much of this scholarship would have us believe (Platt and Squire 2017). Of course, this is not a new observation, nor is this paper the first to think harder about what ornament did in Roman painting. Work on the Egyptian motifs that appear in frescoes of the first centuries BCE and CE has long emphasised the ways in which ornamental details might communicate aspects of political or religious identity and engage viewers in discourses on luxury (see Pearson 2015, with bibliography). Likewise, the last decade has produced much valuable research on many of the non-figurative and seemingly marginal features of ancient mural schemes, including 'still lives' and the trompe l'oeil depiction of objects (Bergmann 2010;O'Connell 2015), imitation marble (Fant 2007;McAlpine 2014;Platt 2018), painted frames (Platt 2009;Squire 2017), and the related topic of inlaid wall ornaments (Powers 2011). Part of a larger-scale reappraisal of ornament 1 The scholarship on Roman painting is substantial, but typical approaches include (Ling 1991, pp. 128-35;Wallace-Hadrill 1994;Bergmann 1995;Elsner 1995, pp. 21-48;Hales 2003;Leach 2004;Croisille 2005, pp. 23, 169-92;Lorenz 2008;Marvin 2008, pp. 194-205;Newby 2016). For critique see, inter alia, (Swift 2009;Powers 2011;Rouveret 2015;Platt and Squire 2017;Squire 2018).
Third Style paintings of 'cubiculum 4' from the Villa of Numidius Popidius Florus also at Boscoreale and now in the J. Paul Getty Museum in Los Angeles (acc. no. 70.AG.91).
I argue that all three schemes harness the material affordances of gemstones to augment the appearance of vividness and to engage the viewer in their pictorial illusion. At the same time, promoting gems' eye-like qualities also recalibrates the viewer's subjectivity, opening opportunities for further seduction. Considering the representational and referential significance of the gemstones, I additionally suggest that their captivating look not only made the fresco more convincingly 'real', but also advocated the desirability of the fresco-patron's social ideologies by giving a positive gloss to two persistent themes in ancient discourses against gems-as-ornament, namely their slipperiness as objects that confuse art and nature, and their intimate association with female adornment and seduction. As well as highlighting the importance of sensory stimulation to the ancient reception of mural art, therefore, I argue that looking closer at painted gemstones sheds brighter light on the ways in which elite patrons deployed fresco ornament to promote the pleasures of wealth, luxuria, and cultus.

Looking at Gems: A Literary Lens
Like other Graeco-Roman ekphrases, ancient descriptions of gemstones are paradigmatic of a sensualist approach to viewing and intellectualizing encounters with artworks, exemplifying what James I. Porter has termed an "aesthetic materialism" characteristic of the Hellenistic and Roman periods (Porter 2011, p. 272). However, in evoking the material qualities of gems, these ekphrases also present precious stones as objects that are themselves uniquely vivid and powerfully sensual. In particular, Posidippus's Lithika provides a series of aesthetic reactions to gemstones that delights in their tactility and eye-catching brilliance, celebrating what we might term the 'poikilia' of their colour, radiance, and sensitivity to changing light, as well as their exotic provenance, miniature size, and wondrous craftsmanship (Gutzwiller 2005;Rush 2012;Elsner 2014). This helps us to formulate a strategy for the evaluation of real stones and their painted equivalents specifically in terms of the variegation and illumination of surface, and on the interplay of touching and looking.
The majority of Posidippus's gems are defined by their vivid colour and sparkling luminosity, which is frequently likened to that of the sun and the moon (e.g., 4.3, 5.1, and 16.6). The intaglio described in poem 13 is a literal light mass, a ϕ´ γγoς . . . Second Style paintings of 'cubiculum M' from the Villa of Publius Fannius Synistor at Boscoreale, now in the Metropolitan Museum of Art in New York (acc. no. 03.14.13a-g); the early Third Style paintings of 'cubiculum B' from the Augustan villa under the Farnesina, now in the Palazzo Massime alle Terme in Rome; and the Third Style paintings of 'cubiculum 4' from the Villa of Numidius Popidius Florus also at Boscoreale and now in the J. Paul Getty Museum in Los Angeles (acc. no. 70.AG.91). I argue that all three schemes harness the material affordances of gemstones to augment the appearance of vividness and to engage the viewer in their pictorial illusion. At the same time, promoting gems' eye-like qualities also recalibrates the viewer's subjectivity, opening opportunities for further seduction. Considering the representational and referential significance of the gemstones, I additionally suggest that their captivating look not only made the fresco more convincingly 'real', but also advocated the desirability of the fresco-patron's social ideologies by giving a positive gloss to two persistent themes in ancient discourses against gems-as-ornament, namely their slipperiness as objects that confuse art and nature, and their intimate association with female adornment and seduction. As well as highlighting the importance of sensory stimulation to the ancient reception of mural art, therefore, I argue that looking closer at painted gemstones sheds brighter light on the ways in which elite patrons deployed fresco ornament to promote the pleasures of wealth, luxuria, and cultus.

Looking at Gems: A Literary Lens
Like other Graeco-Roman ekphrases, ancient descriptions of gemstones are paradigmatic of a sensualist approach to viewing and intellectualizing encounters with artworks, exemplifying what James I. Porter has termed an "aesthetic materialism" characteristic of the Hellenistic and Roman periods (Porter 2011, p. 272). However, in evoking the material qualities of gems, these ekphrases also present precious stones as objects that are themselves uniquely vivid and powerfully sensual. In particular, Posidippus's Lithika provides a series of aesthetic reactions to gemstones that delights in their tactility and eye-catching brilliance, celebrating what we might term the 'poikilia' of their colour, radiance, and sensitivity to changing light, as well as their exotic provenance, miniature size, and wondrous craftsmanship (Gutzwiller 2005;Rush 2012;Elsner 2014). This helps us to formulate a strategy for the evaluation of real stones and their painted equivalents specifically in terms of the variegation and illumination of surface, and on the interplay of touching and looking.
The majority of Posidippus's gems are defined by their vivid colour and sparkling luminosity, which is frequently likened to that of the sun and the moon (e.g., 4.3, 5.1, and 16.6). The intaglio described in poem 13 is a literal light mass, a φέγγος … ὄγκους that sends out rays of light when made wet with oil, only revealing its carved image when dry. As Porter notes, the Greek term, ogkos, denotes 'surface' as well as 'bulk', shifting attention from the gem's substance to its appearance and transforming it into a screen "on which aesthetic effects appear and disappear, fleetingly" (Porter 2011, p. 285). However, we might better think of this gem as a miniature lamp, enlivening the surface it adorns with its flickering, transient light. This is made literal in poem 7, where a honey-coloured stone mounted in a necklace illuminates its wearer, Nikonoe's, breast with a golden glow. Other authors emphasise gems' light-giving properties in similar terms: Pliny the Elder's catalogue of gems, contained in book 37 of his Natural History, lists numerous examples of precious stones that flash brilliantly or seem to contain stars, casting light on the fingers that hold them (e.g., NH 37. 80-81; 37.83; 37.92; 37.100). Both he and Lucian also mention a type of fiery red stone known as a lychnis that glows like a torch in the evening (Pliny NH 37.103; Lucian De Dea Syria 31-32).
These descriptions recall the rhetorical habit of comparing the enlivening effects of verbal ornament to bright light, as in the Ad Herennium, or when Cicero likens Caesar's use of oratoria ornamenta to placing a well-painted picture in good light (Brutus 261). This encourages us to give the fresco gems similar agency, enlivening the mural with their colour and light. And yet, by conjuring the sweetness of honey and the caress of female flesh, Posidippus's lamp-like gem excites touch and taste as well, not only making (parts of) Nikonoe more visible, but making her more palpable, too. Pre-empting Ovid's Pygmalion , who adorns his statue γκoυς that sends out rays of light when made wet with oil, only revealing its carved image when dry. As Porter notes, the Greek term, ogkos, denotes 'surface' as well as 'bulk', shifting attention from the gem's substance to its appearance and transforming it into a screen "on which aesthetic effects appear and disappear, fleetingly" (Porter 2011, p. 285). However, we might better think of this gem as a miniature lamp, enlivening the surface it adorns with its flickering, transient light. This is made literal in poem 7, where a honey-coloured stone mounted in a necklace illuminates its wearer, Nikonoe's, breast with a golden glow. Other authors emphasise gems' light-giving properties in similar terms: Pliny the Elder's catalogue of gems, contained in book 37 of his Natural History, lists numerous examples of precious stones that flash brilliantly or seem to contain stars, casting light on the fingers that hold them (e.g., NH 37. 80-81; 37.83; 37.92; 37.100). Both he and Lucian also mention a type of fiery red stone known as a lychnis that glows like a torch in the evening (Pliny NH 37.103; Lucian De Dea Syria 31-32).
These descriptions recall the rhetorical habit of comparing the enlivening effects of verbal ornament to bright light, as in the Ad Herennium, or when Cicero likens Caesar's use of oratoria ornamenta to placing a well-painted picture in good light (Brutus 261). This encourages us to give the fresco gems similar agency, enlivening the mural with their colour and light. And yet, by conjuring the sweetness of honey and the caress of female flesh, Posidippus's lamp-like gem excites touch and taste as well, not only making (parts of) Nikonoe more visible, but making her more palpable, too. Pre-empting Ovid's Pygmalion , who adorns his statue with gems in order to make her more convincing as a real girl (Elsner 2007, pp. 115-31), this jewel even brings life and warmth to Nikonoe's pale white body so that stone and skin "glow together". The same is true of Posidippus's ϕ´ γγoς . . . their tactility and eye-catching brilliance, celebrating what we might term the 'poikilia' of their colour, radiance, and sensitivity to changing light, as well as their exotic provenance, miniature size, and wondrous craftsmanship (Gutzwiller 2005;Rush 2012;Elsner 2014). This helps us to formulate a strategy for the evaluation of real stones and their painted equivalents specifically in terms of the variegation and illumination of surface, and on the interplay of touching and looking.
The majority of Posidippus's gems are defined by their vivid colour and sparkling luminosity, which is frequently likened to that of the sun and the moon (e.g., 4.3, 5.1, and 16.6). The intaglio described in poem 13 is a literal light mass, a φέγγος … ὄγκους that sends out rays of light when made wet with oil, only revealing its carved image when dry. As Porter notes, the Greek term, ogkos, denotes 'surface' as well as 'bulk', shifting attention from the gem's substance to its appearance and transforming it into a screen "on which aesthetic effects appear and disappear, fleetingly" (Porter 2011, p. 285). However, we might better think of this gem as a miniature lamp, enlivening the surface it adorns with its flickering, transient light. This is made literal in poem 7, where a honey-coloured stone mounted in a necklace illuminates its wearer, Nikonoe's, breast with a golden glow. Other authors emphasise gems' light-giving properties in similar terms: Pliny the Elder's catalogue of gems, contained in book 37 of his Natural History, lists numerous examples of precious stones that flash brilliantly or seem to contain stars, casting light on the fingers that hold them (e.g.,37.83;37.92;37.100). Both he and Lucian also mention a type of fiery red stone known as a lychnis that glows like a torch in the evening (Pliny NH 37.103; Lucian De Dea Syria 31-32).
These descriptions recall the rhetorical habit of comparing the enlivening effects of verbal ornament to bright light, as in the Ad Herennium, or when Cicero likens Caesar's use of oratoria ornamenta to placing a well-painted picture in good light (Brutus 261). This encourages us to give the fresco gems similar agency, enlivening the mural with their colour and light. And yet, by conjuring the sweetness of honey and the caress of female flesh, Posidippus's lamp-like gem excites touch and taste as well, not only making (parts of) Nikonoe more visible, but making her more palpable, too. Pre-empting Ovid's Pygmalion (Metamorphoses 10.243-298), who adorns his statue γκoυς, moistened with oil. Oil, honey, and wax were sometimes used to enhance the colour and polish of precious stones (Pliny NH 37.71;37.195), as well as to conceal imperfections (Elsner 2014, p. 159;Nassau 1984, p. 23), but the verb that Posidippus uses-λιπα[ινoµ´ νη]ς, meaning 'anointing' or 'greasing'-also alludes to the oiling of athletes' muscles and the perfuming of women's bodies. For Posidippus, then, looking at and touching gems were easily compatible, implicitly erotic acts. Many of the stones he describes are given as love-tokens, often in exchange for a kiss, and at least half are worn or admired by women (Elsner 2014, pp. 163-64). Nor is he the only writer to make intimate contact central to gems' appreciation, or to emphasise how touching gems could make them easier to see. Tibullus uses the conceit of examining the device on his beloved's gemstone as an opportunity to caress her hand (1.6.25), while Ovid transforms the common practice of wetting the surface of engraved stones with the lips or the tongue to make their images clearer into an erotic fantasy (Amores 2.16). This helps us to think about painted gemstones as objects for sensing, as points of enargeia that enlivened the fresco surface with colour, light, and tactile allure, enhancing the convincing illusionism of the mural scheme by evoking memories of seeing and handling real stones. It also ties painted gems' powers of visual persuasion to real gems' capacity for physical seduction. The proem to the second book of Philostratus's Imagines makes this emphatic (Imag. 2.1). Here, a painting of a statue of Aphrodite is framed by precious stones so realistic that the artist appears to have painted with light rather than with colour, giving them a radiance "like the pupil in an eye" (o with gems in order to make her more convincing as a real girl (Elsner 2007, pp. 115-31), this jewel even brings life and warmth to Nikonoe's pale white body so that stone and skin "glow together". The same is true of Posidippus's φέγγος … ὄγκους, moistened with oil. Oil, honey, and wax were sometimes used to enhance the colour and polish of precious stones (Pliny NH 37.71;37.195), as well as to conceal imperfections (Elsner 2014, p. 159;Nassau 1984, p. 23), but the verb that Posidippus uses-λιπα[ινομένη]ς, meaning 'anointing' or 'greasing'-also alludes to the oiling of athletes' muscles and the perfuming of women's bodies. For Posidippus, then, looking at and touching gems were easily compatible, implicitly erotic acts. Many of the stones he describes are given as love-tokens, often in exchange for a kiss, and at least half are worn or admired by women (Elsner 2014, pp. 163-64). Nor is he the only writer to make intimate contact central to gems' appreciation, or to emphasise how touching gems could make them easier to see. Tibullus uses the conceit of examining the device on his beloved's gemstone as an opportunity to caress her hand (1.6.25), while Ovid transforms the common practice of wetting the surface of engraved stones with the lips or the tongue to make their images clearer into an erotic fantasy (Amores 2.16). This helps us to think about painted gemstones as objects for sensing, as points of enargeia that enlivened the fresco surface with colour, light, and tactile allure, enhancing the convincing illusionism of the mural scheme by evoking memories of seeing and handling real stones. It also ties painted gems' powers of visual persuasion to real gems' capacity for physical seduction. The proem to the second book of Philostratus's Imagines makes this emphatic (Imag. 2.1). Here, a painting of a statue of Aphrodite is framed by precious stones so realistic that the artist appears to have painted with light rather than with colour, giving them a radiance "like the pupil in an eye" (ο ἷ ον ὁ φθαλμ ῷ κέντρον). On one hand, then, the description confirms that painted gems evoked the material brilliance of real stones, and that this in turn might enhance the illusory reality of the painting. It also implies a conceptual synonymy between gems and eyes that rests on their shared material properties. Indeed, the simile is far from an isolated example: Pliny cites a number of stones that are 'eye-like' in colour, shape, and shine, including a type of Persian smaragdus (perhaps green turquoise), which glows like a cat's eyes (NH 37.69;see also NH 37.110,37.133,37.149,37.155,and 37.168), and a colourless star-stone (asteria), which also contains a light "like the pupil of an eye" (quod inclusam lucem pupilla quadam continet) (Pliny NH 37.131). However, as Platt argues, Philostratus's gem-eyes also take us "beyond the boundaries of representation" by seeming to perform the goddess' epiphany, suggesting divine radiance at the same time as lending the statue a subjectivity of its own (Platt 2011, pp. 5-7). The activation of Aphrodite's image in this way is contingent on the sensory stimulation of the stones: They evoke Aphrodite's appearances in myth, where her revelation to mortal eyes is often recognised through the glitter of her jewels, which in turn enhance the eroticism of her body-as, for example, in the Homeric Hymn 5 when the goddess appears to Anchises glittering with jewels. Like Nikonoe, the gems not only help us to see Aphrodite, they help us to touch her, too.
The association also gives the gemstones the 'look of love', and reminds us that in the ancient sources, Aphrodite's physical charm is located as much in her eyes as in her jewellery or her body (e.g., Apuleius Met. 10.30). The amorous gaze that "melts what it looks upon", is, in fact, an established literary trope "central to the poetic expression of erotic desire" (Calame 2016, p. 300). Love is frequently described as 'darting' from the eyes of goddesses and beautiful women, arousing and disarming the beholder: In Hesiod, for example, the Graces emit love-beams from their sparkling eyes like rays of light, undoing whoever catches their gaze (Theogony 907ff; Catalogues of Women frr. 14 and 68), and Sophocles describes how the eyes of a happily wedded bride emanate all-conquering desire (Antigone 795-796). In a poem by Ibycus, Eros himself casts the poet a melting gaze that throws him "into the nets of Aphrodite" (PMGF 287;trans. Calame 2016, p. 299).
Flashing and gleaming, these beguiling love-eyes have a liquid quality not unlike the brilliant poikilia of precious stones, tying gems' symbolic value unavoidably to their capacity to enchant. This is, of course, already implicit in Posidippus, as also in the real-world custom of wearing gems to attract lovers, but a number of literary sources follow Philostratus and specifically exploit the eye-like quality of precious stones to signal the compelling power of adornment. Pliny notes that with gems in order to make her more convincing as a real girl (Elsner 2007, pp. 115-31), this jewel even brings life and warmth to Nikonoe's pale white body so that stone and skin "glow together". The same is true of Posidippus's φέγγος … ὄγκους, moistened with oil. Oil, honey, and wax were sometimes used to enhance the colour and polish of precious stones (Pliny NH 37.71;37.195), as well as to conceal imperfections (Elsner 2014, p. 159;Nassau 1984, p. 23), but the verb that Posidippus uses-λιπα[ινομένη]ς, meaning 'anointing' or 'greasing'-also alludes to the oiling of athletes' muscles and the perfuming of women's bodies. For Posidippus, then, looking at and touching gems were easily compatible, implicitly erotic acts. Many of the stones he describes are given as love-tokens, often in exchange for a kiss, and at least half are worn or admired by women (Elsner 2014, pp. 163-64). Nor is he the only writer to make intimate contact central to gems' appreciation, or to emphasise how touching gems could make them easier to see. Tibullus uses the conceit of examining the device on his beloved's gemstone as an opportunity to caress her hand (1.6.25), while Ovid transforms the common practice of wetting the surface of engraved stones with the lips or the tongue to make their images clearer into an erotic fantasy (Amores 2.16). This helps us to think about painted gemstones as objects for sensing, as points of enargeia that enlivened the fresco surface with colour, light, and tactile allure, enhancing the convincing illusionism of the mural scheme by evoking memories of seeing and handling real stones. It also ties painted gems' powers of visual persuasion to real gems' capacity for physical seduction. The proem to the second book of Philostratus's Imagines makes this emphatic (Imag. 2.1). Here, a painting of a statue of Aphrodite is framed by precious stones so realistic that the artist appears to have painted with light rather than with colour, giving them a radiance "like the pupil in an eye" (ο ἷ ον ὁ φθαλμ ῷ κέντρον). On one hand, then, the description confirms that painted gems evoked the material brilliance of real stones, and that this in turn might enhance the illusory reality of the painting. It also implies a conceptual synonymy between gems and eyes that rests on their shared material properties. Indeed, the simile is far from an isolated example: Pliny cites a number of stones that are 'eye-like' in colour, shape, and shine, including a type of Persian smaragdus (perhaps green turquoise), which glows like a cat's eyes (NH 37.69;see also NH 37.110,37.133,37.149,37.155,and 37.168), and a colourless star-stone (asteria), which also contains a light "like the pupil of an eye" (quod inclusam lucem pupilla quadam continet) (Pliny NH 37.131). However, as Platt argues, Philostratus's gem-eyes also take us "beyond the boundaries of representation" by seeming to perform the goddess' epiphany, suggesting divine radiance at the same time as lending the statue a subjectivity of its own (Platt 2011, pp. 5-7). The activation of Aphrodite's image in this way is contingent on the sensory stimulation of the stones: They evoke Aphrodite's appearances in myth, where her revelation to mortal eyes is often recognised through the glitter of her jewels, which in turn enhance the eroticism of her body-as, for example, in the Homeric Hymn 5 when the goddess appears to Anchises glittering with jewels. Like Nikonoe, the gems not only help us to see Aphrodite, they help us to touch her, too.
The association also gives the gemstones the 'look of love', and reminds us that in the ancient sources, Aphrodite's physical charm is located as much in her eyes as in her jewellery or her body (e.g., Apuleius Met. 10.30). The amorous gaze that "melts what it looks upon", is, in fact, an established literary trope "central to the poetic expression of erotic desire" (Calame 2016, p. 300). Love is frequently described as 'darting' from the eyes of goddesses and beautiful women, arousing and disarming the beholder: In Hesiod, for example, the Graces emit love-beams from their sparkling eyes like rays of light, undoing whoever catches their gaze (Theogony 907ff; Catalogues of Women frr. 14 and 68), and Sophocles describes how the eyes of a happily wedded bride emanate all-conquering desire (Antigone 795-796). In a poem by Ibycus, Eros himself casts the poet a melting gaze that throws him "into the nets of Aphrodite" (PMGF 287; trans. Calame 2016, p. 299).
Flashing and gleaming, these beguiling love-eyes have a liquid quality not unlike the brilliant poikilia of precious stones, tying gems' symbolic value unavoidably to their capacity to enchant. This is, of course, already implicit in Posidippus, as also in the real-world custom of wearing gems to attract lovers, but a number of literary sources follow Philostratus and specifically exploit the eye-like quality of precious stones to signal the compelling power of adornment. Pliny notes that ϕθαλµ Arts 2019, 8, x FOR PEER REVIEW with gems in order to make her more co even brings life and warmth to Nikonoe's The same is true of Posidippus's φέγγ sometimes used to enhance the colour and as to conceal imperfections (Elsner 2014, uses-λιπα[ινομένη]ς, meaning 'anointin muscles and the perfuming of women's b were easily compatible, implicitly erot love-tokens, often in exchange for a kiss, 2014, pp. 163-64). Nor is he the only write to emphasise how touching gems could examining the device on his beloved's ge Ovid transforms the common practice of tongue to make their images clearer into a This helps us to think about painted enlivened the fresco surface with colo illusionism of the mural scheme by evoki painted gems' powers of visual persuasio to the second book of Philostratus's Imag statue of Aphrodite is framed by preciou with light rather than with colour, giving φθαλμ ῷ κέντρον). On one hand, then material brilliance of real stones, and th painting. It also implies a conceptual syn material properties. Indeed, the simile is f that are 'eye-like' in colour, shape, and sh turquoise), which glows like a cat's eyes 37.168), and a colourless star-stone (aster (quod inclusam lucem pupilla quadam co However, as Platt argues, Philostra representation" by seeming to perform t same time as lending the statue a subje Aphrodite's image in this way is conting Aphrodite's appearances in myth, where the glitter of her jewels, which in turn en Homeric Hymn 5 when the goddess app gems not only help us to see Aphrodite, t The association also gives the gemst sources, Aphrodite's physical charm is lo (e.g., Apuleius Met. 10.30). The amorou established literary trope "central to the Love is frequently described as 'darting' f and disarming the beholder: In Hesiod sparkling eyes like rays of light, undoing Women frr. 14 and 68), and Sophocles de all-conquering desire (Antigone 795-796). gaze that throws him "into the nets of Ap Flashing and gleaming, these beguil poikilia of precious stones, tying gems' sym is, of course, already implicit in Posidipp attract lovers, but a number of literary eye-like quality of precious stones to sig κ´ ντρoν). On one hand, then, the description confirms that painted gems evoked the material brilliance of real stones, and that this in turn might enhance the illusory reality of the painting. It also implies a conceptual synonymy between gems and eyes that rests on their shared material properties. Indeed, the simile is far from an isolated example: Pliny cites a number of stones that are 'eye-like' in colour, shape, and shine, including a type of Persian smaragdus (perhaps green turquoise), which glows like a cat's eyes (NH 37.69;see also NH 37.110,37.133,37.149,37.155,and 37.168), and a colourless star-stone (asteria), which also contains a light "like the pupil of an eye" (quod inclusam lucem pupilla quadam continet) (Pliny NH 37.131).
However, as Platt argues, Philostratus's gem-eyes also take us "beyond the boundaries of representation" by seeming to perform the goddess' epiphany, suggesting divine radiance at the same time as lending the statue a subjectivity of its own (Platt 2011, pp. 5-7). The activation of Aphrodite's image in this way is contingent on the sensory stimulation of the stones: They evoke Aphrodite's appearances in myth, where her revelation to mortal eyes is often recognised through the glitter of her jewels, which in turn enhance the eroticism of her body-as, for example, in the Homeric Hymn 5 when the goddess appears to Anchises glittering with jewels. Like Nikonoe, the gems not only help us to see Aphrodite, they help us to touch her, too.
The association also gives the gemstones the 'look of love', and reminds us that in the ancient sources, Aphrodite's physical charm is located as much in her eyes as in her jewellery or her body (e.g., Apuleius Met. 10.30). The amorous gaze that "melts what it looks upon", is, in fact, an established literary trope "central to the poetic expression of erotic desire" (Calame 2016, p. 300). Love is frequently described as 'darting' from the eyes of goddesses and beautiful women, arousing and disarming the beholder: In Hesiod, for example, the Graces emit love-beams from their sparkling eyes like rays of light, undoing whoever catches their gaze (Theogony 907ff; Catalogues of Women frr. 14 and 68), and Sophocles describes how the eyes of a happily wedded bride emanate all-conquering desire (Antigone 795-796). In a poem by Ibycus, Eros himself casts the poet a melting gaze that throws him "into the nets of Aphrodite" (PMGF 287; trans. Calame 2016, p. 299).
Flashing and gleaming, these beguiling love-eyes have a liquid quality not unlike the brilliant poikilia of precious stones, tying gems' symbolic value unavoidably to their capacity to enchant. This is, of course, already implicit in Posidippus, as also in the real-world custom of wearing gems to attract lovers, but a number of literary sources follow Philostratus and specifically exploit the eye-like quality of precious stones to signal the compelling power of adornment. Pliny notes that amethysts were Arts 2019, 8, 60 6 of 26 known as "eyelids of Venus" (NH 37.123) because of their captivating colour, and we hear elsewhere of a magical amethyst engraved with a love-charm and dedicated to Aphrodite that had the power to draw men across the sea and boys from their bedrooms (AP 5.205). Numerous 'non-magical' stones were also thought to have electrostatic or magnetic properties by ancient writers (e.g., Pliny NH.103).
Achilles Tatius, meanwhile, likens a gem worn by a bride to a golden eye, as though it were charged with the same sexual magnetism as Aphrodite's glinting gaze (Leucippe and Clitophon 2.11.2-4). The amethyst paid for Charikleia's ransom in Hesiodorus's Aethiopica (5.13) is also compared in size to a maiden's eye, implying the interchangeable desirability of gemstones and women. In the world of Roman elegy, women's jewels and women's eyes exert a comparably irresistible pull on the helpless poet-lover (Propertius 1.1.1 and 2.22a.10). This makes the use of real gems as eye inlays in Greek and Roman sculpture about more than just replicating lifelikeness in terms of colour and sheen (Hoft 2015, p. 123); it gives the statue the limb-loosening look of the beloved, reminding us that the persuasive force of illusionistic representation depended as much on the evocation of desire in the viewer as on realism (Valladares 2011). The same conceit is played out more subtly in Roman-period mummy portraits, where Egyptian blue pigment could be used to replicate the lustrous surfaces of eyes and jewels, as on a second-century CE portrait of a woman now in London (British Museum, acc. no. 1939,0324.211: Verri 2009Brecoulaki 2015, pp. 230-31) (Figure 1). Turned into twin points of shimmering luminescence, the gem and eye activate the portrait (Corcoran 2016, p. 63), accentuating the gaze, but also giving the deceased subject a compelling-perhaps desirous-presence in the viewer's world. amethysts were known as "eyelids of Venus" (NH 37.123) because of their captivating colour, and we hear elsewhere of a magical amethyst engraved with a love-charm and dedicated to Aphrodite that had the power to draw men across the sea and boys from their bedrooms (AP 5.205). Numerous 'non-magical' stones were also thought to have electrostatic or magnetic properties by ancient writers (e.g., Pliny NH.103). Achilles Tatius, meanwhile, likens a gem worn by a bride to a golden eye, as though it were charged with the same sexual magnetism as Aphrodite's glinting gaze (Leucippe and Clitophon 2.11.2-4). The amethyst paid for Charikleia's ransom in Hesiodorus's Aethiopica (5.13) is also compared in size to a maiden's eye, implying the interchangeable desirability of gemstones and women. In the world of Roman elegy, women's jewels and women's eyes exert a comparably irresistible pull on the helpless poet-lover (Propertius 1.1.1 and 2.22a.10). This makes the use of real gems as eye inlays in Greek and Roman sculpture about more than just replicating lifelikeness in terms of colour and sheen (Hoft 2015, p. 123); it gives the statue the limb-loosening look of the beloved, reminding us that the persuasive force of illusionistic representation depended as much on the evocation of desire in the viewer as on realism (Valladares 2011). The same conceit is played out more subtly in Roman-period mummy portraits, where Egyptian blue pigment could be used to replicate the lustrous surfaces of eyes and jewels, as on a second-century CE portrait of a woman now in London (British Museum, acc. no. 1939,0324.211: Verri 2009Brecoulaki 2015, pp. 230-31) (Figure 1). Turned into twin points of shimmering luminescence, the gem and eye activate the portrait (Corcoran 2016, p. 63), accentuating the gaze, but also giving the deceased subject a compelling-perhaps desirous-presence in the viewer's world. Egyptian blue might also be used for statues' eyes instead of precious stones (Verri et al. 2010, pp. 48-49), and this potential for gems to be eyes and for pigment to be both has obvious implications for the depiction of precious stones in wall painting and their capacity to seduce. As Egyptian blue might also be used for statues' eyes instead of precious stones (Verri et al. 2010, pp. 48-49), and this potential for gems to be eyes and for pigment to be both has obvious implications for the depiction of precious stones in wall painting and their capacity to seduce. As Platt has observed, Philostratus's painted gem-eyes expose a tension between intellectual and sensory perception, signalling the artist's techne at the same time as persuading the viewer of their reality and calling what Jas' Elsner has termed the "process of realist viewing" into question by (Elsner 1995, p. 74;Squire 2013, p. 111). Not only can their appearance not be trusted but by looking back at their viewer, the gems deny their status as a viewed object altogether. For the viewer of the real frescoes we are about to examine, this enacts a potential reversal of subjectivity, giving the impression instead of being looked at by the image. If these gems are like women's eyes, by which to be gazed at is to be undone with desire, then becoming the object of the fresco's look is to be exposed fully to the painting's charms.

The Villa of Publius Fannius Synistor
To examine more carefully how these material associations played out in Roman wall painting, I focus now on three examples of decorative mural schemes, which, like Philostratus's painting, depict gems as ornament on their borders. First are the wall paintings of 'cubiculum M' from the villa of Publius Fannius Synistor at Boscoreale on the Bay of Naples, painted in c.  In this room, the north, east, and west walls' central scenes are each framed by a pair of red marble columns, crowned with golden Corinthian capitals and entwined with gold tendrils with gem-studded blossoms that spring from calyxes of gold acanthus leaves ( Figure 2). They are part of a fantasy construction of trompe l'oeil architecture emblematic of the theatrical and carefully crafted illusionism of the Second Style of Pompeian wall painting (Drerup 1959;Ehrhardt 1991, pp. 28-30;Ling 1991, pp. 23-51). Confounding the room's physical limits, they seemingly transform its walls into a colonnade through which a series of panoramas are glimpsed (Platt 2017, pp. 102-6;Clarke 1993, p. 33). Divided into antechamber and alcove, the east and west walls both appear to open onto a fanciful cityscape with one courtyard containing an elaborate shrine and another with a tholos temple, both adorned with garlands, gold statues, and precious metal vessels. The north wall, by contrast, opens onto a rustic sanctuary within a grotto with fountains overhung by ivy and a terrace with grapevines beyond. Platt has observed, Philostratus's painted gem-eyes expose a tension between intellectual and sensory perception, signalling the artist's techne at the same time as persuading the viewer of their reality and calling what Jas' Elsner has termed the "process of realist viewing" into question by (Elsner 1995, p. 74;Squire 2013, p. 111). Not only can their appearance not be trusted but by looking back at their viewer, the gems deny their status as a viewed object altogether. For the viewer of the real frescoes we are about to examine, this enacts a potential reversal of subjectivity, giving the impression instead of being looked at by the image. If these gems are like women's eyes, by which to be gazed at is to be undone with desire, then becoming the object of the fresco's look is to be exposed fully to the painting's charms.

The Villa of Publius Fannius Synistor
To examine more carefully how these material associations played out in Roman wall painting, I focus now on three examples of decorative mural schemes, which, like Philostratus's painting, depict gems as ornament on their borders. First are the wall paintings of 'cubiculum M' from the villa of Publius Fannius Synistor at Boscoreale on the Bay of Naples, painted in c.  In this room, the north, east, and west walls' central scenes are each framed by a pair of red marble columns, crowned with golden Corinthian capitals and entwined with gold tendrils with gem-studded blossoms that spring from calyxes of gold acanthus leaves ( Figure 2). They are part of a fantasy construction of trompe l'oeil architecture emblematic of the theatrical and carefully crafted illusionism of the Second Style of Pompeian wall painting (Drerup 1959;Ehrhardt 1991, pp. 28-30;Ling 1991, pp. 23-51). Confounding the room's physical limits, they seemingly transform its walls into a colonnade through which a series of panoramas are glimpsed (Platt 2017, pp. 102-6;Clarke 1993, p. 33). Divided into antechamber and alcove, the east and west walls both appear to open onto a fanciful cityscape with one courtyard containing an elaborate shrine and another with a tholos temple, both adorned with garlands, gold statues, and precious metal vessels. The north wall, by contrast, opens onto a rustic sanctuary within a grotto with fountains overhung by ivy and a terrace with grapevines beyond. The bibliography on the villa as a whole and on cubiculum M in particular is expansive. Key publications include (Lehmann 1953;Beyen 1957;Ling 1991, pp. 28-30;Clarke 1993, p. 33;Bergmann 2002Bergmann , 2013Bergmann et al. 2010;Verbank-Piérard et al. 2013). The bibliography on the villa as a whole and on cubiculum M in particular is expansive. Key publications include (Williams-Lehmann 1953;Beyen 1957;Ling 1991, pp. 28-30;Clarke 1993, p. 33;Bergmann 2002Bergmann , 2013Bergmann et al. 2010;Verbank-Piérard and Barbet 2013). These columns, together with the near-identical gold versions painted in triclinium 14 of Villa A at Oplontis, have primarily been used as evidence for the opulence of late Republican villa decoration and its efforts to emulate the sumptuous and glittering interiors of Hellenistic palaces (Williams-Lehmann 1953, p. 87;Lapatin 2015, p. 119;Bergmann 2010, p. 32). Greek and Roman texts provide a number of parallels, including the gilt gem-studded columns that reportedly supported the pavilion of Alexander, and the gold columns with golden acanthus tendrils that decorated his hearse (Diodorus Siculus Bib. 18.272; Athenaeus Deip. 12.538d). Citing Callimachus, Athenaeus tells us that columns decorated with ivory and gold adorned Ptolemy IV Philadelphos's pleasure boat (Athenaeus Deip. 5.204), while Lucan describes the agate columns and emerald-studded ivory veneers that clad the walls of Cleopatra's reception hall in Alexandria, where she entertained Julius Caesar on couches inlaid with gems and furnished with covers embroidered with jaspers (De Bello Civ. 10.111-122).
Fragments of gilded bronze set with over four hundred gemstones, including agates, amethysts, chalcedonies, and garnets, have been excavated in the Horti Maecenatis on the Oppian Hill in Rome, confirming that Roman interiors were embellished with real jewels, too (Cima 1986, pp. 105-44;Lapatin 2015, p. 121;Häuber 2015, pp. 803-6). Perhaps most famous is Nero's Domus Aurea, which, according to Suetonius, contained rooms entirely covered with gold and adorned with gems and mother-of-pearl (Suet. Nero 31.2.), but in the Julio-Claudian period, such ostentatious decoration seems to have been commonplace amongst Rome's wealthiest citizens, and was increasingly problematized as a marker of dangerous, Eastern luxury (Tacitus Annals 15.42.1; Seneca the Younger Epistles 86.6-7). Not only did these gem-encrusted interiors allow Romans to act like Hellenistic kings in their homes, it also allowed them to act like gods (Barry 2013, p. 86). Similar decorations to those found on the Oppian Hill were recovered from the sanctuary of Aphrodite at Amathus on Cyprus (Häuber 2015, p. 803), while Lucan explicitly likens Cleopatra's lavish palace to a temple (De Bello Civili 10.112).
Real gems-contained in cabinets like those described in Posidippus's Lithika, or as decoration on luxurious metal objects-were also conspicuous in late Republican Rome as plunder, paraded during triumphal processions, displayed publicly in the Forum, and dedicated in temples (Pliny NH 37.11; Suetonius Aug. 30.2.4). Most notorious is Pompey's triumph commemorating his defeat of Mithridates of Pontus in 64 BCE, which brought a glut of precious stones into the city and supposedly ignited a gem-mania amongst Roman elites, contributing to the spread of Greek luxus at Rome and her consequent moral decline (Pliny NH 37.12-18). This positions gems as objects, the significance of which rested on their status as exotic luxury and foreign import, and on their (sometimes problematic) association with imperial expansion and triumphal display, making them easily symbolic of unregulated wealth and greed (for this as an overarching concern of Pliny's Natural History, see Carey 2003, especially ch. 4). Marble columns, often stolen from Greek temples, also found their way to Rome as plunder, where they sometimes decorated elaborate private villas and were problematized by critics on the same terms as precious stones (Leach 2004, pp. 29-30).
The gemmed-columns at Boscoreale consequently conjure the material splendour of Roman triumph as well as the seductive opulence of Eastern palaces and, later, imperial domi (Wallace-Hadrill 2008, pp. 315-55; Zarmakoupi 2014, pp. 50-61;Clarke 1993, pp. 12-26;Bergmann 2013). This is underlined by the use of cinnabar for the red column shafts (Meyer 2010, p. 34), which was a costly foreign import mined beyond the reaches of the Empire itself (Spangenberg et al. 2010). The columns even purport to be real spolia: Each one is in fact an individual plaster section (Meyer and Faltermeier 2010 at 11:30), inserted separately into the cubiculum walls as though truly taken from a conquered temple (or palace) and erected as decorative trophy. It is no surprise, therefore, that each pair frames a shrine, either alluding to their fictive provenance or elevating their display to votive dedication. The association with sacred architecture is made more explicit on close inspection of the tholoi painted on the east and west walls of the alcove, the red columns of which are also decorated with spiralling tendrils and topped with golden Corinthian capitals. 6 The rinceaux motif itself was closely associated with Dionysus (Sauron 1988, p. 15), and as the Hellenistic comparanda suggest could be used to signpost otherworldly or superhuman status, whether divine, royal, or deceased. In the Augustan period, it came to symbolise the god-given abundance and renewal of the first principate (Castriota 1995).
Where we could, therefore, see these jewelled columns as symbolic "shifters" marking the transition from divine to domestic or from fiction to reality (Bergmann 2010, p. 29), their presentation as sacred spolia turned decor transforms them into objects for aesthetic contemplation connected intimately with contemporary debates concerning empire, luxuria, and wealth. As Clare Guest observes, the display of looted artworks in Rome was a means of ornamenting the city, enhancing its splendour and prestige at the same time as creating an appropriate setting for the pursuit of leisure, pleasure, and cultured sophistication (Guest 2015, p. 134). Gems are in many ways the ultimate objet d'art, catching the eye and demanding close up viewing, and the skill with which they have been represented on the walls of cubiculum M invites similar connoisseurial appreciation. At first glance, they are convincingly material. The variegated colours and shapes of the stones-either square-cut and faceted or convex and oval-recall the emeralds, amethysts, chalcedonies, and garnets imported and quarried across the Roman world and popular in first-century BCE jewellery (Zazoff 1983, pp. 270, 348;Plantzos 1999, p. 36;Mulliez-Tramond 2010, p. 131). The use of gold settings also reflects contemporary taste and its preference for poikilia: According to Pliny, for example, yellow beryls should be hexagonally-cut and backed with gold as a way of enhancing their brilliance (NH 37.106), later adding that no stone sets off gold so well as green emeralds (NH 37.112). The painter of the Boscoreale gems has replicated this effect by applying each 'stone' over the gold of its mount-which is itself modelled with shadow and highlight-and using tonal gradations of colour to modulate its surface, suggesting three-dimensionality, translucency, and shine.
White highlights on the surface of each stone, applied with quick, fluid brushstrokes, further simulate the phenomenal appearance of actual gems by seeming to reflect the light in the room. In triclinium 14 at Oplontis, highlights on metal objects contain Egyptian blue so that they sparkled for real (Gee 2015, p. 142). The pigment may also have been used on the jewels adorning the gold columns (personal communication Regina Gee), and although no pigment analysis has been done on the gems from Boscoreale (personal communication Joan Mertens and Christl Faltermeier), the same artists worked at both sites (Bergmann 2002, p. 95;2010, p. 11;Gee 2015, p. 129), suggesting it may have been used there, too. Egyptian blue has been detected on other sections of the walls of cubiculum M (Meyer 2010, p. 44), while the evidence of the Roman mummy portraits attests to the practice of using the pigment for precious stones, giving them 'eye-like' radiance and subjectivity of their own. Even if Egyptian blue was not used, the shape of the stones and their near-liquid shimmer still reminds the viewer of eyes. The plaster, which was polished to a mirror-like sheen and mixed with marble dust in the uppermost layer, would also have glittered as it caught the light, enhancing the gems' apparent material radiance (Meyer 2010, p. 33).
If we are to follow Philostratus, then being confronted by so many eye-like gems had the effect of turning the viewer from a connoisseur of painterly skill to a captive of the stones' enticing glimmer. Enthralled, he or she might imitate Tibullus and imagine reaching out to caress a jewel, or else to pluck one from its setting, like the covetous dinner-guests Juvenal describes stealing gems from embellished metal drinking cups (5.65-76); as though to encourage this response, a bird on the north wall seems about to snatch a stone with its beak (Figure 3). On one hand, then, this appeal to touch enhances the suggestion of texture and volume, giving the fresco greater three-dimensionality. However, it also makes tangible the desirability of the room's luxurious materialism. 6 The gold gem-encrusted columns at Oplontis likewise frame doors to sanctuaries, and a Fourth Style fresco from the House of Menander in Pompeii depicts a shrine with gold Corinthian columns entwined with silver ivy leaves (Maiuri 1932, figs. 44-46, pl. X;Clarke 1993, p. 115). At this point, however, the eye-like radiance of the stones takes on a different-perhaps more threatening-quality. In his Metamorphoses, Ovid uses the Latin 'gemma' to denote the jewel-like 'eyes' of the peacock's tail (Met. 1.723), which we are told were in fact real eyes taken by Juno from the slain giant, Argus. Known by the epithet, Panoptes ('All-Eyed'), and renowned for his ever-alert wakefulness, Argus had been tasked by a jealous Juno to 'keep an eye' on the nymph-turned-heifer, Io, and guard her from Jupiter's lustful advances. Although ultimately unsuccessful, to be Argus-eyed consequently became a metaphor for close observation and the guarding of covetable goods: So, Propertius gazes intently at his beloved Cynthia, "like Argus on the strange horn's of Inachus's child [Io]" (Argus ut ignotis cornibus Inachidos) (1.3.30).
Other writers describe Argus's many eyes as flashing and gleaming (e.g., Hyginus Fabulae 145; Nonnus Dionysiaca 13.26), recalling the language used to describe the radiance of precious stones. By making the suggestive similarity literal, however, Ovid's description not only picks up on real gems' eye-like physicality and their persistent literary analogy, but also reflects the apparent use of precious stones for surveillance: According to Suetonius, the colonnades of Domitian's Domus Flavia were lined with a type of reflective, transparent stone that enabled the emperor to see what was happening behind him (Suet. Dom. 14.2). This encourages us to think of painted gems as metaphorical spyglasses, too, a poetic ploy that is in fact made material in the Fourth Style fresco decoration of Villa A at Oplontis. Here, a golden trophy cista depicted on the wall of room 5 is decorated with a wreath set with three green gemstones painted by the same hand and with the same formal characteristics as the green 'eyes' of a peacock's tail in room 70 (Gee 2015 p. 142) ( Figure  4). It would be hard for a viewer versed in Ovid to look at the peacock and not think of Argus's watchful eyes and so, encouraged by the visual similarity, to see them reflected in the cista gems, too. Keeping an eye out for covetous fingers, these painted gem-eyes consequently remind the viewer that the villa's luxury (both real and represented) is off limits. At this point, however, the eye-like radiance of the stones takes on a different-perhaps more threatening-quality. In his Metamorphoses, Ovid uses the Latin 'gemma' to denote the jewel-like 'eyes' of the peacock's tail (Met. 1.723), which we are told were in fact real eyes taken by Juno from the slain giant, Argus. Known by the epithet, Panoptes ('All-Eyed'), and renowned for his ever-alert wakefulness, Argus had been tasked by a jealous Juno to 'keep an eye' on the nymph-turned-heifer, Io, and guard her from Jupiter's lustful advances. Although ultimately unsuccessful, to be Argus-eyed consequently became a metaphor for close observation and the guarding of covetable goods: So, Propertius gazes intently at his beloved Cynthia, "like Argus on the strange horn's of Inachus's child [Io]" (Argus ut ignotis cornibus Inachidos) (1.3.30).
Other writers describe Argus's many eyes as flashing and gleaming (e.g., Hyginus Fabulae 145; Nonnus Dionysiaca 13.26), recalling the language used to describe the radiance of precious stones. By making the suggestive similarity literal, however, Ovid's description not only picks up on real gems' eye-like physicality and their persistent literary analogy, but also reflects the apparent use of precious stones for surveillance: According to Suetonius, the colonnades of Domitian's Domus Flavia were lined with a type of reflective, transparent stone that enabled the emperor to see what was happening behind him (Suet. Dom. 14.2). This encourages us to think of painted gems as metaphorical spyglasses, too, a poetic ploy that is in fact made material in the Fourth Style fresco decoration of Villa A at Oplontis. Here, a golden trophy cista depicted on the wall of room 5 is decorated with a wreath set with three green gemstones painted by the same hand and with the same formal characteristics as the green 'eyes' of a peacock's tail in room 70 (Gee 2015) (Figure 4). It would be hard for a viewer versed in Ovid to look at the peacock and not think of Argus's watchful eyes and so, encouraged by the visual similarity, to see them reflected in the cista gems, too. Keeping an eye out for covetous fingers, these painted gem-eyes consequently remind the viewer that the villa's luxury (both real and represented) is off limits.  At Boscoreale, then, we might also see the many-eyed columns as an abstracted Argus, guarding the precious goods depicted beyond their boundary. However, that is not all that the literary association of gems with (peacock-)eyes entails. For Phaedrus, who uses 'gemma' in the same way as Ovid, the superficial glamour of the 'gems' belies the peacock's ugly singing voice (Fabulae 3.18.3), suggesting the potential for painted jewels also to signal the unreliability of vision-or rather, the deceptive look of decorated surfaces. Certainly, by going nearer to the painted gems, the viewer is made aware that what they see is only surface. As in Philostratus's proem, the gem-ornament here illuminates the conditions of illusionistic representation and the painterly skill on which the entire mural scheme depends-even as it makes the fresco more compelling (Platt 2017, p. 111).
I suggest that at Boscoreale, this tension in turn becomes a means of conceptualising and contextualising the relationship between art and nature. As has been much explored, Latin authors considered ars and natura to be related phenomena, separable only by degree (Bergmann 2002, p. 88), and precious stones prove especially emblematic of this trope. For Posidippus, as for other Hellenistic poets, the incredible lifelikeness of intaglio gems' engraved images made them At Boscoreale, then, we might also see the many-eyed columns as an abstracted Argus, guarding the precious goods depicted beyond their boundary. However, that is not all that the literary association of gems with (peacock-)eyes entails. For Phaedrus, who uses 'gemma' in the same way as Ovid, the superficial glamour of the 'gems' belies the peacock's ugly singing voice (Fabulae 3.18.3), suggesting the potential for painted jewels also to signal the unreliability of vision-or rather, the deceptive look of decorated surfaces. Certainly, by going nearer to the painted gems, the viewer is made aware that what they see is only surface. As in Philostratus's proem, the gem-ornament here illuminates the conditions of illusionistic representation and the painterly skill on which the entire mural scheme depends-even as it makes the fresco more compelling (Platt 2017, p. 111).
I suggest that at Boscoreale, this tension in turn becomes a means of conceptualising and contextualising the relationship between art and nature. As has been much explored, Latin authors considered ars and natura to be related phenomena, separable only by degree (Bergmann 2002, p. 88), and precious stones prove especially emblematic of this trope. For Posidippus, as for other Hellenistic poets, the incredible lifelikeness of intaglio gems' engraved images made them paradigms of artistic skill (Gutzwiller 2005, p. 383;Rush 2012, pp. 26-60), but for Pliny, gems represented a perfect contemplation of nature, albeit one vulnerable to misuse as luxury (NH 37.1). 7 It is no coincidence that Ovid includes gemstones in a list of raw materials that are crude by nature, but made elegant by artistry (Ars 3.219-224); nor, conversely, that reports existed of miraculous gems 'engraved' with naturally-occurring rather than manmade motifs (Pliny NH 37.5).
Elsewhere in Latin literature gems are linked etymologically to buds and vegetation (Cicero de Sen. 15.53; Vergil Georgics 2.335; Pliny NH 37.62-63), reminding us that ornament might literally bring life as well as beauty to whatever surface it adorned (Guest 2015, p. 150). Lucretius takes the analogy further, however, conjuring the image of trees covered in gems rather than flowers as an example of impossible, unnatural, hybridity (De Rerum Natura 5.912). More than just a nod to Hellenistic fashion, therefore, the use of precious stones for blossoms on the cubiculum columns is a visual pun that acknowledges gems' potential to be both artful and natural; or, rather, to be nature transformed into art. They symbolise the work of culture, and establish this as a mode for viewing the cubiculum frescoes as a whole: The shrines on the north, east, and west walls are made analogous by the repeated glitter of the jewelled columns that frame them, presenting both rustic and urban vistas as comparable products of human craftsmanship. This is underlined by the acanthus motif itself, which is often associated with refined artistry in Latin poetry (Vergil Eclogues 3.45; Aeneid 1.649; Theocritus 1.55-56) and evokes Dionysus's twin association with seasonal regeneration and the luxury (or artifice) of the theatre (Guest 2015, p. 127). So, the golden tendrils of the columns on the north wall echo the trailing ivy of the grotto and the grapevines beyond, setting the natural against the artificial, but ultimately presenting both as painterly fabrication (Platt 2017, p. 109).
Indeed, the north wall-immediately visible from the entrance to the room, and so prominent within the composition as a whole-pushes the interplay of art and nature further. As is well known, a window imposes 'reality' over the trompe l'oeil fiction of the fresco, located in part within the column-frame, but cutting through the left-hand shaft and a corner of a yellow monochrome screen supporting a glass bowl of fruit ( Figure 5). Bevelled edges to the wall painting confirm that the window already existed when the frescoes were executed (Meyer 2010, p. 44), while the trompe l'oeil shadows on the east and west walls have been painted as though responding to light from the window (Williams-Lehmann 1953, p. 88). This makes the juxtaposition of the natural and the artificial, of the real and the painted, central to the mural design. Other details add to the effect. For example, the fruits contained in the bowl are painted the same vivid colours and shaped with the same tonal shadows and white highlights as the jewels, establishing a formal correspondence that equates natural produce to artificial blossom. Equally tempting, they render luxus and fructus comparatively desirable, and suggest both might have ornamental function. This recalls the Stoic philosophy laid out in Cicero's De Naturam , which presents nature's diversity as earth's adornment, to be cultivated and improved (or, literally, brightened) by mankind (Guest 2015, p. 37).
The yellow panel itself depicts a harbour scene with temples, porticoes, and villa structures in the distance (Figure 6). Visually and physically joined to what would have been a real view of nature outside the window (Bergmann 2010, p. 14), this is an image that showcases, in Cicero's terms, the brightening work of manmade ornament, and that frames the Roman villa as a symbol of cultivated luxuria (Bergmann 1991;Zarmakoupi 2014). Although the panel is commonly described as a marble bas-relief (Mulliez-Tramond 2010, p. 135;Platt 2017, p. 112), the figures and buildings are impressionistically rendered with loose creamy brushstrokes that recall the highlights on the columns' jewels and instead suggest a reflective, perhaps even translucent surface. More than on marble, this is how images appear on intaglio and cameo gems when held up to the light, shimmering on the edge of visibility. In fact, a first-century CE cornelian intaglio in St. Petersburg is carved with a very similar seaside scene, with sailboats, fishermen, and a coastal villa (The State Hermitage Museum, inv. ГР-21685) (Figure 7); the stone glows yellow when lit from behind. 7 On luxury as an abuse of nature, see (Zanda 2011, p. 1;Bradley 2009, p. 88).     Although there is no archaeological evidence that carved precious stone panels of this size were used as wall inlays in the Roman period, we know that cameo glass panels were (Powers 2011, pp. 19-20). Two blue glass cameo plaques depicting Dionysiac scenes were found in the House of Marcus Fabius Rufus in Pompeii (VII,16,22) (Maiuri 1961, pp. 154-57), and excavations on the Oppian Hill in Rome recovered several large blocks of unengraved amethyst that may have been set into walls or columns (Häuber 2015, p. 805). Glass revetments have also been found at the villa of Lucius Verus at Aqua Traversa near Rome (Hemsoll 1990;Barry 2013, pp. 83-84) and in a number of houses in Pompeii and Herculaneum (Vipard 2003). Whether fantasy or not, by conjuring the appearance of highly wrought translucent stone, the panel offers an alternative 'view-through' to that provided by both the real window and the fictive vistas beyond the painted colonnades. 8 The juxtaposition of window and fresco already presents the fabricated world of the artwork and the 'natural' world of the villa estate as equivalent works of culture. This marks Boscoreale as the ideal villa rustica, combining material opulence with agricultural productivity (Zarmakoupi 2014;Bergmann 2002Bergmann , 2013, and the villa's patron as curator and cultivator of his estate. However, if we think of even this 'gemstone' as an eye, then the panel also offers a concentrated counterpoint to the anti-luxury invective of contemporary commentators, harnessing gems' capacity to entice in order to promote or reinforce the desirability of the kind of materialistic luxury living Boscoreale afforded. Pliny implies that gemstones could provide a soothing filter-or tempting look-for potentially discomfiting sights by relating how Nero watched gladiator fights through an emerald screen (NH 37.64). Given Nero's infamous fascination with gladiators, we might say this gem seduced the viewer as well as softening the view (e.g., Suet. Nero 30.2), intimating at how the Boscoreale jewels may likewise have charmed their audience. 8 Durchblicke ('views-through') and Ausblicke (vistas) are characteristic features of Second Style wall painting, the former denoting the recession of space through architectural structures (Drerup 1959;Ehrhardt 1991). Although there is no archaeological evidence that carved precious stone panels of this size were used as wall inlays in the Roman period, we know that cameo glass panels were (Powers 2011, pp. 19-20). Two blue glass cameo plaques depicting Dionysiac scenes were found in the House of Marcus Fabius Rufus in Pompeii (VII, 16, 22) (Maiuri 1961, pp. 154-57), and excavations on the Oppian Hill in Rome recovered several large blocks of unengraved amethyst that may have been set into walls or columns (Häuber 2015, p. 805). Glass revetments have also been found at the villa of Lucius Verus at Aqua Traversa near Rome (Hemsoll 1990;Barry 2013, pp. 83-84) and in a number of houses in Pompeii and Herculaneum (Vipard 2003). Whether fantasy or not, by conjuring the appearance of highly wrought translucent stone, the panel offers an alternative 'view-through' to that provided by both the real window and the fictive vistas beyond the painted colonnades. 8 The juxtaposition of window and fresco already presents the fabricated world of the artwork and the 'natural' world of the villa estate as equivalent works of culture. This marks Boscoreale as the ideal villa rustica, combining material opulence with agricultural productivity (Zarmakoupi 2014;Bergmann 2002Bergmann , 2013, and the villa's patron as curator and cultivator of his estate. However, if we think of even this 'gemstone' as an eye, then the panel also offers a concentrated counterpoint to the anti-luxury invective of contemporary commentators, harnessing gems' capacity to entice in order to promote or reinforce the desirability of the kind of materialistic luxury living Boscoreale afforded. Pliny implies that gemstones could provide a soothing filter-or tempting look-for potentially discomfiting sights by relating how Nero watched gladiator fights through an emerald screen (NH 37.64). Given Nero's infamous fascination with gladiators, we might say this gem seduced the viewer as well as softening the view (e.g., Suet. Nero 30.2), intimating at how the Boscoreale jewels may likewise have charmed their audience. 8 Durchblicke ('views-through') and Ausblicke (vistas) are characteristic features of Second Style wall painting, the former denoting the recession of space through architectural structures (Drerup 1959;Ehrhardt 1991).

The Villa under the Farnesina
The illusionistic architecture of the Second Style transformed during the 20s BCE into abstracted, miniaturist confections that no longer denied the spatial limits of the room, but instead provided ornamental frames for Greek style panel-pictures (pinakes) painted as though truly hanging on the wall (Bastet and de Vos 1979;Scagliarini 1974Scagliarini -1976. This so-called Third Style of Pompeian painting is defined by what Agnès Rouveret has termed an "aesthetics of intimacy" that privileged slenderness, delicacy, and the small-scale, facilitating displays of connoisseurship and refined taste by encouraging close-up, slow-paced viewing and so providing a visual complement to the elegance and self-conscious classicism of Augustan literature (Rouveret 2015;Platt 2009, p. 44;Clarke 1993, p. 49).
If the painted gems on the walls of the Villa of Publius Fannius Synistor advocated the bombastic, world-facing materialism of the late Republic, then their Third Style equivalents were as integral to the promotion of this new mode of rarefied, private looking. Real gemstones were celebrated in literature for their virtuoso miniaturist carving and flashy materiality, which attracted attention and rewarded close examination (Allen 2016, pp. 25-27). Gems consequently lent themselves to contexts of privileged viewing and the one-to-one display of artistic erudition, and so were much coveted during the Augustan period by an imperial elite eager to showcase their sophisticated appreciation of Greek culture: It is no surprise that early imperial gems are distinctively Greek in style and subject matter (Plantzos 1999, p. 94), or that antique examples with genuine Greek provenance were especially sought after (Pliny NH 37.3-7; Juvenal 6.156-157). Perhaps the most notorious connoisseur of this time was Maecenas, who we know decorated the walls of his domus with real jewels, and who accrued an impressive personal collection (NH 8.170). He even appears to have written poetry about gems (Petrain 2005, pp. 344-49). Plutarch also describes a man known as a ϕιλoλίθoς (a "lover of precious stones"), who is delighted when a friend asks to study one of his intaglios (De Ira. Coh. 462d).
However, as we have already seen, gemstones were objects of erotic desire as well as symbols of wealth and status, hinting at how the intellectual frisson of looking at gems might slide into something more sensual. In elegy and satire, gems adorn the bodies of high-class prostitutes and adulterous wives (e.g., Horace Sat. 1.2.80; Propertius 2.16.11-16; 2.22a.10; Tibullus 1.6.24 and 2.4.21-30; Juvenal 6.457-460), who wear them to attract lovers or else demand them in exchange for sex, rendering them synonymous with female licentiousness (Olson 2008, p. 20;Kapparis 2017, pp. 88-91). Perhaps the most infamous jewelled woman in imperial literature is Cleopatra, who we are told dressed herself, Aphrodite-like, with emeralds and other precious stones in order to seduce Mark Antony and Julius Caesar (Plutarch Antony 26.1-4; NH 9.119-21). Engraved gems were given as love tokens in this period, too (Henig 1995, p. 74), and the popularity of images of Aphrodite, Dionysus, and their respective entourages only makes gems' association with voluptuousness and pleasure more emphatic (Allen 2016, pp. 89-90).
As such, the choice to depict gemstones as decoration in Third Style frescoes pushes Rouveret's aesthetic of intimate viewing into one of tactile, sensuous delight, promoting the desirability of refinement itself. The conceit is already established in the early Augustan villa under the Farnesina in Rome, which was possibly owned by Agrippa (Moorman 2010), and is now preserved in the Palazzo Massimo. Bridging the transition from the Second to the Third Style (Clarke 1993, p. 12), the walls of 'cubiculum B' are decorated with a series of framed 'panel-pictures' some of which are executed with a delicate line and formal style reminiscent of 5th-century BCE Athenian vase-painting (Platt 2009, p. 41). These pinakes are 'mounted' within a trompe l'oeil aedicula of coloured marble plinths, pilasters, and architraves, including imitation wrought metal plaques chased with floral motifs set with illusionistic cabuchon gems (Bragantini and de Vos 1982, pp. 39, 128-39, 155) (Figure 8). Just as at Boscoreale, these painted jewels enhance the tactile materiality of the fresco and the convincing suggestion of three-dimensionality. By evoking the look and feel of real gem-encrusted objects, they also bring to mind contemporary contexts of acquisition and display, celebrating material splendour as a boon of empire. It is no surprise, therefore, that they are located on the walls of a cubiculum: Amongst other functions, this was a room that was considered an appropriate space for exhibiting prized artworks, including paintings, sculptures, and gemstones (Riggsby 1997, pp. 38-39). appropriate space for exhibiting prized artworks, including paintings, sculptures, and gemstones (Riggsby 1997, pp. 38-39). The gems' association with sensual pleasure is also emphatic. Mounted on faux marble orthostats, these gem-studded plaques help create the setting for the central pinax on the left wall, which depicts Aphrodite seated at her toilette, attended by one of the Graces and a winged Eros (Figure 9). Painted in elegant outline on white-ground, minute detail and thin washes of precisely applied colour draw attention to the delicacy and finesse of the goddess' ornaments, including her ornate crown, gold jewellery, elaborate sandals, and diaphanous purple drapery. Each figure is, moreover, shown holding a different luxury object-a slender sceptre by Eros, a gauzy veil by the Grace, and a delicate purple flower by Aphrodite herself-that visualise the intimacies of refinement and further excite the viewer's desire to touch.
Looking at Aphrodite's flower, it is hard not to think of the goddess' association with amethysts, which are likened by Xenophon of Ephesus to pale purple buds, just beginning to open (Aethiopica 5.13). In fact, the bloom echoes two purple-tinted faux silver rosettes that adorn the aedicula directly above the painting, and that each carry a blue cabuchon gemstone at their centre (Bragantini and de Vos,pl. 43,p. 130). It also mirrors the gem that Eros wears on his chest mounted on a gold body-chain. Riffing once more on the dual meaning of gemma, this triangulation of blossom, gemstone, and flower-like jewel conflates the erotics of Aphrodite's toilette-which we know from myth is always a precursor to seduction-with the sensory delights of luxurious décor. If, as several scholars have suggested, the painting's classicising style afforded its viewer a chance to exhibit their knowledge of Greek art history (Squire 2017, pp. 606-11), then this appeal to the pleasures of adornment also extolled the attractions of cultured sophistication. However, that is not all. Positioned like a pair of eyes above the pinax, the gem-flowers once again turn the viewer of the painting into a viewed object: Their looking at Aphrodite looking at the flower is observed and made public. As Elsner has argued with regard to depictions of Narcissus within the Roman house, this refraction of sightlines makes viewing itself the subject of the painting (Elsner 2007, p. 175). In a world in which the display and discussion of art was a marker of status and privilege, these gems put the viewer's connoisseurship and erudition in the spotlight. The gems' association with sensual pleasure is also emphatic. Mounted on faux marble orthostats, these gem-studded plaques help create the setting for the central pinax on the left wall, which depicts Aphrodite seated at her toilette, attended by one of the Graces and a winged Eros (Figure 9). Painted in elegant outline on white-ground, minute detail and thin washes of precisely applied colour draw attention to the delicacy and finesse of the goddess' ornaments, including her ornate crown, gold jewellery, elaborate sandals, and diaphanous purple drapery. Each figure is, moreover, shown holding a different luxury object-a slender sceptre by Eros, a gauzy veil by the Grace, and a delicate purple flower by Aphrodite herself-that visualise the intimacies of refinement and further excite the viewer's desire to touch.
Looking at Aphrodite's flower, it is hard not to think of the goddess' association with amethysts, which are likened by Xenophon of Ephesus to pale purple buds, just beginning to open (Aethiopica 5.13). In fact, the bloom echoes two purple-tinted faux silver rosettes that adorn the aedicula directly above the painting, and that each carry a blue cabuchon gemstone at their centre (Bragantini and de Vos,pl. 43,p. 130). It also mirrors the gem that Eros wears on his chest mounted on a gold body-chain. Riffing once more on the dual meaning of gemma, this triangulation of blossom, gemstone, and flower-like jewel conflates the erotics of Aphrodite's toilette-which we know from myth is always a precursor to seduction-with the sensory delights of luxurious décor. If, as several scholars have suggested, the painting's classicising style afforded its viewer a chance to exhibit their knowledge of Greek art history (Squire 2017, pp. 606-11), then this appeal to the pleasures of adornment also extolled the attractions of cultured sophistication. However, that is not all. Positioned like a pair of eyes above the pinax, the gem-flowers once again turn the viewer of the painting into a viewed object: Their looking at Aphrodite looking at the flower is observed and made public. As Elsner has argued with regard to depictions of Narcissus within the Roman house, this refraction of sightlines makes viewing itself the subject of the painting (Elsner 2007, p. 175). In a world in which the display and discussion of art was a marker of status and privilege, these gems put the viewer's connoisseurship and erudition in the spotlight.

The Villa of Numerius Popidius Florus
To demonstrate how the depiction of gems developed in the mature Third Style, I turn now to the fragmentary frescoes from cubiculum 4 in the Villa of Numerius Popidius Florus, also at Boscoreale, and painted in the first half of the first century CE (Schefold 1960, p. 92, pl. 4;1962, p. 95, pl. 172, 1;Vermeule and Neuerberg 1973, pp. 42-43, no. 93;Oettel 1996, pp. 250-51, no. 21.5c). What would have been the central section of one wall is decorated with a network of slender candelabras and attenuated Corinthian columns supporting ornate entablatures that surround a yellow faux-marble panel on which a framed pinax appears to hang ( Figure 10). This pinax depicts a seated man looking at a draped woman who stands with one arm resting on her hip and the other about to pull a veil from her shoulders. We do not know who these figures are, but the man is characterised as a philosopher of the Cynic school by his ragged clothing, bare feet, and dishevelled beard. The woman, meanwhile, is often catalogued as a courtesan. While this need not be true, her body language and dress hint at sexual availability. Her pose replicates a well-known Aphrodite statue-type that shows the goddess toying with her veil (e.g., Naples, Museo Archaeologico Nazionale, inv. no. 6396), as well as the numerous images of women undressing that were popular on engraved gemstones. A first-century CE glass cameo in New York, for example, shows a nude woman picked out in white holding her mantle behind her as though in the final stages of a striptease (Metropolitan Musuem of Art,acc. no. 74.51.4244) (Figure 11).

The Villa of Numerius Popidius Florus
To demonstrate how the depiction of gems developed in the mature Third Style, I turn now to the fragmentary frescoes from cubiculum 4 in the Villa of Numerius Popidius Florus, also at Boscoreale, and painted in the first half of the first century CE (Schefold 1960, p. 92, pl. 4;1962, p. 95, pl. 172, 1;Vermeule and Neuerberg 1973, pp. 42-43, no. 93;Oettel 1996, pp. 250-51, no. 21.5c). What would have been the central section of one wall is decorated with a network of slender candelabras and attenuated Corinthian columns supporting ornate entablatures that surround a yellow faux-marble panel on which a framed pinax appears to hang ( Figure 10). This pinax depicts a seated man looking at a draped woman who stands with one arm resting on her hip and the other about to pull a veil from her shoulders. We do not know who these figures are, but the man is characterised as a philosopher of the Cynic school by his ragged clothing, bare feet, and dishevelled beard. The woman, meanwhile, is often catalogued as a courtesan. While this need not be true, her body language and dress hint at sexual availability. Her pose replicates a well-known Aphrodite statue-type that shows the goddess toying with her veil (e.g., Naples, Museo Archaeologico Nazionale, inv. no. 6396), as well as the numerous images of women undressing that were popular on engraved gemstones. A first-century CE glass cameo in New York, for example, shows a nude woman picked out in white holding her mantle behind her as though in the final stages of a striptease (Metropolitan Musuem of Art, acc. no. 74.51.4244) (Figure 11). The woman's gesture at Boscoreale is by consequence a visual come-on, directing her viewer (both painted and real) to think about removing her clothing by him or herself, and her diaphanous purple robe only emphasises her physical allure further: As well as by Aphrodite, purple was worn by brides and by prostitutes (Kapparis 2017, pp. 86-89;Oakley and Sinos 1993, p. 16). Cynics famously rejected physical and material desires, including luxury and sex, yet this philosopher appears transfixed by the (promise of the) woman's disrobing; she may be the object of his-and the viewer of the fresco's-gaze, but she is active in manipulating his desire. Like the Farnesina pinax, therefore, this is an image that delights in tempting its viewer to touch.
On its own, this is perhaps unremarkable, but I suggest that more is at play here. Across the top of the panel is a narrow grid-like frieze, painted in white and containing alternating purple and green squares. In terms of colour and form, the band replicates the appearance of an emerald and amethyst-set necklace or diadem: We might compare the first-century CE necklace of gold and emerald beads excavated in villa B at Oplontis (Gazda and Clarke 2016, no. 186), or a late first-century BCE gold leaf diadem in Los Angeles decorated with green glass and purple garnets (J. Paul Getty Museum, 75.AM.60) (Figure 12). An early second-century CE funerary portrait from The woman's gesture at Boscoreale is by consequence a visual come-on, directing her viewer (both painted and real) to think about removing her clothing by him or herself, and her diaphanous purple robe only emphasises her physical allure further: As well as by Aphrodite, purple was worn by brides and by prostitutes (Kapparis 2017, pp. 86-89;Oakley and Sinos 1993, p. 16). Cynics famously rejected physical and material desires, including luxury and sex, yet this philosopher appears transfixed by the (promise of the) woman's disrobing; she may be the object of his-and the viewer of the fresco's-gaze, but she is active in manipulating his desire. Like the Farnesina pinax, therefore, this is an image that delights in tempting its viewer to touch.
On its own, this is perhaps unremarkable, but I suggest that more is at play here. Across the top of the panel is a narrow grid-like frieze, painted in white and containing alternating purple and green squares. In terms of colour and form, the band replicates the appearance of an emerald and amethyst-set necklace or diadem: We might compare the first-century CE necklace of gold and emerald beads excavated in villa B at Oplontis (Gazda and Clarke 2016, no. 186), or a late first-century BCE gold leaf diadem in Los Angeles decorated with green glass and purple garnets (J. Paul Getty Museum, 75.AM.60) (Figure 12). An early second-century CE funerary portrait from Hawara now in London shows a woman wearing two similar necklaces of emeralds and amethysts strung with gold (British Museum, acc. no. 1994,0521.4) (Figure 13). Hawara now in London shows a woman wearing two similar necklaces of emeralds and amethysts strung with gold (British Museum, acc. no. 1994,0521.4) ( Figure 13).  As Sarah Pearson has observed, scholars have long recognized a jewel-like quality to Third Style painting, but seldom acknowledge that mural artists may in fact have been deliberately copying jewellery (Pearson 2015, p. 39). By referencing contemporary jewellery, the Boscoreale frieze expresses familiar delight in luxury goods, but unlike the three-dimensionally-modelled gems from the Farnesina or the Villa of Publius Fannius Synistor, these stones do not attempt to convince the viewer of any material reality. The frieze has instead transposed the formal contingencies of real jewellery into linear, two-dimensional decoration; even the fine white lines of the boxes that frame the stones on the fresco simulate the appearance of light catching on the edges of real gem settings, turned into a netlike pattern. Rendered in paint, the gems have been recast unavoidably as ornamental motif.
Such flatness is characteristic of the Third Style (Clarke 1993, p. 273), and has the effect of focusing the attention on the fresco surface itself. In so doing, the gem-ornament plays on a common literary trope-implicit, too, in the Farnesina frescoes-that elided female adornment with Hawara now in London shows a woman wearing two similar necklaces of emeralds and amethysts strung with gold (British Museum, acc. no. 1994,0521.4) ( Figure 13).  As Sarah Pearson has observed, scholars have long recognized a jewel-like quality to Third Style painting, but seldom acknowledge that mural artists may in fact have been deliberately copying jewellery (Pearson 2015, p. 39). By referencing contemporary jewellery, the Boscoreale frieze expresses familiar delight in luxury goods, but unlike the three-dimensionally-modelled gems from the Farnesina or the Villa of Publius Fannius Synistor, these stones do not attempt to convince the viewer of any material reality. The frieze has instead transposed the formal contingencies of real jewellery into linear, two-dimensional decoration; even the fine white lines of the boxes that frame the stones on the fresco simulate the appearance of light catching on the edges of real gem settings, turned into a netlike pattern. Rendered in paint, the gems have been recast unavoidably as ornamental motif.
Such flatness is characteristic of the Third Style (Clarke 1993, p. 273), and has the effect of focusing the attention on the fresco surface itself. In so doing, the gem-ornament plays on a common literary trope-implicit, too, in the Farnesina frescoes-that elided female adornment with As Sarah Pearson has observed, scholars have long recognized a jewel-like quality to Third Style painting, but seldom acknowledge that mural artists may in fact have been deliberately copying jewellery (Pearson 2015, p. 39). By referencing contemporary jewellery, the Boscoreale frieze expresses familiar delight in luxury goods, but unlike the three-dimensionally-modelled gems from the Farnesina or the Villa of Publius Fannius Synistor, these stones do not attempt to convince the viewer of any material reality. The frieze has instead transposed the formal contingencies of real jewellery into linear, two-dimensional decoration; even the fine white lines of the boxes that frame the stones on the fresco simulate the appearance of light catching on the edges of real gem settings, turned into a netlike pattern. Rendered in paint, the gems have been recast unavoidably as ornamental motif.
Such flatness is characteristic of the Third Style (Clarke 1993, p. 273), and has the effect of focusing the attention on the fresco surface itself. In so doing, the gem-ornament plays on a common literary trope-implicit, too, in the Farnesina frescoes-that elided female adornment with architectural decoration. Already in the second century BCE, Plautus uses verbs of polishing and adorning to describe a courtesan's toilette 229) and the application of costly finishing touches to a house (Plautus Mostellaria pp. 101, 126), presenting the former as an example of unacceptable luxus (Nichols 2010, pp. 47-56). In Augustan elegy, women's makeup is likened to stucco, gilding, and paint, reminding us that the materials used for cosmetics and jewellery were often the same as those used by ancient artists to adorn domestic spaces (Olson 2008, p. 309). Lucian meanwhile warns against making speeches in grand buildings, where words are overwhelmed by ornate interiors in the same way that an overly adorned woman is masked by the glitter of her jewels (Lucian De Domo 15). architectural decoration. Already in the second century BCE, Plautus uses verbs of polishing and adorning to describe a courtesan's toilette 229) and the application of costly finishing touches to a house (Plautus Mostellaria pp. 101, 126), presenting the former as an example of unacceptable luxus (Nichols 2010, pp. 47-56). In Augustan elegy, women's makeup is likened to stucco, gilding, and paint, reminding us that the materials used for cosmetics and jewellery were often the same as those used by ancient artists to adorn domestic spaces (Olson 2008, p. 309). Lucian meanwhile warns against making speeches in grand buildings, where words are overwhelmed by ornate interiors in the same way that an overly adorned woman is masked by the glitter of her jewels (Lucian De Domo 15). The transformation of gem-set jewellery to fresco motif, from one medium and order of representation to another, is also an example of the kind of artificial mannerism that concerned Vitruvius in his discussion of early imperial wall painting and was condemned as a marker of luxury (De Arch. 7.5.3). However, where writers use the analogy of personal adornment to domestic ornament to condemn the artificiality of women's constructed appearances (see e.g., Sharrock 1991;Rimell 2006, p. 1;Wyke 1994, pp. 141-46), I suggest that the cubiculum fresco turns this anxiety on its head to instead promote the pleasures of luxurious surface decoration. It is clear from what we have seen that precious stones offered an excuse to touch beautiful women, and that this encouraged the viewer of painted gems to think about caressing the stones similarly. However, in cubiculum 4, there is no pretence that touching these gems would be any different to touching the wall, transferring their allure to the fresco itself. Indeed, the stones are applied to the fresco as secco overpainting, like jewels to a body (personal communication Maria Svoboda; see also Clarke 1987, p. 269). The transformation of gem-set jewellery to fresco motif, from one medium and order of representation to another, is also an example of the kind of artificial mannerism that concerned Vitruvius in his discussion of early imperial wall painting and was condemned as a marker of luxury (De Arch. 7.5.3). However, where writers use the analogy of personal adornment to domestic ornament to condemn the artificiality of women's constructed appearances (see e.g., Sharrock 1991;Rimell 2006, p. 1;Wyke 1994, pp. 141-46), I suggest that the cubiculum fresco turns this anxiety on its head to instead promote the pleasures of luxurious surface decoration. It is clear from what we have seen that precious stones offered an excuse to touch beautiful women, and that this encouraged the viewer of painted gems to think about caressing the stones similarly. However, in cubiculum 4, there is no pretence that touching these gems would be any different to touching the wall, transferring their allure to the fresco itself. Indeed, the stones are applied to the fresco as secco overpainting, like jewels to a body (personal communication Maria Svoboda; see also Clarke 1987, p. 269).
Nor are they the only luxury objects to be turned into decoration on the aedicula frame. The Corinthian columns that flank the yellow panel are each topped with a miniature silver jug, the sinuous handles of which echo the angle of the woman's bent elbow, as though aligning her physical allure with their material glamour. Beneath the yellow panel, a tiny vignette depicts a swan grazing alongside a selection of jewel-like fruits, including cherries. Coloured silver and with curving neck, this bird also replicates the appearance of the metal vessels, and is likewise transformed into a comparably luxurious decorative element. A common attribute of Aphrodite, the swan underscores the sensory delight that looking at luxury-and at such artistic playfulness-brings. The cherries conjure pleasure in other ways, too: Reportedly introduced to Italy by Lucullus, who brought trees back to Rome as spoils from his eastern campaigns (Carroll 2015, p. 547), they were a feature of his lavish private gardens on the Pincian hill, which provided a stage-set for his notoriously hedonistic lifestyle (Von Stackelberg 2009, pp. 76-78).
The necklace-frieze consequently provides the thread that links the persuasive delights of female bodies to these material privileges of luxus and elides them all with the fresco itself, translating the eroticism of the panel-picture to the pleasures of the wall painting by drawing the viewer's gaze with their eye-like glimmer and material magnetism. 9 We might even imagine that the frieze represents the woman's jewels, already removed and transferred to (or cast around) the wall-just as in Philostratus's proem. Although not all painted gems in Third Style frescoes framed depictions of women (as in room 25 at Oplontis A), the Boscoreale frieze consequently points to the ways in which the representation of gems as two-dimensional decorative motives not only reflected delight in luxury goods, but enticed desire for them.

Conclusions
By drawing attention to the depiction of gemstones in Second and Third Style wall painting, this paper has attempted to demonstrate the value of taking a closer look at the small details of Roman mural art and of gems in particular-objects which, like ornament itself, have long been side-lined in traditional accounts of Greek and Roman art history (see Lapatin 2015 for historiography). It does not claim to be a comprehensive catalogue of the phenomenon, but instead offers a series of case studies, exploring some of the ways that gems are represented and the impact of that representation on their viewer.
To that end, we have seen that gems-as-ornament proved powerful vehicles of concentrated enargeia, not only enhancing the poikilia of the fresco surface with extra colour and light, but also adding texture and at times sharpening the suggestion of three-dimensionality through their haptic allure. We have suggested this was vital to the convincing illusionism of mural painting. Read alongside literary descriptions of gems and consideration of their cultural symbolism, we have also seen that artists attended closely to the material qualities of precious stones-which could be eye-like in terms of their radiance and their capacity to compel-as a way of engaging the viewer physically with the sensory delight of wall painting and so with the seductions of refinement more broadly. This might be to extol the pleasures of material affluence, the satisfactions of sophisticated connoisseurship, or else the delights of surface embellishment itself, all of which is to argue for the ways in which elites used the depiction of gems to advocate the desirability of luxus in their homes. decoration as others have done, this paper instead gives agency to ornament's superficiality and sensual charm, proposing that the power of painted gems rested in their ability to bring light and life to the surfaces they adorned, making the fresco more vivid and its message persuasively palpable.
Funding: This research received no external funding.