A Review of Boron-Bearing Minerals (Excluding Tourmaline) in the Adirondack Region of New York State

: Boron is a biologically important element, but its distribution in the natural environment and its behavior during many geological processes is not fully understood. In most metamorphic and igneous environments, boron is incorporated into minerals of the tourmaline supergroup. In high-grade metamorphic terranes like that of the Adirondack region of northern New York State, uncommon rock compositions combined with unusual and variable geologic conditions resulted in the formation of many additional boron-bearing minerals. This paper reviews the occurrences and geological settings of twelve relatively uncommon boron-bearing minerals in the southern Grenville Province of upstate New York and provides new chemical and Raman spectral data for seven of these minerals. The boron minerals range from relatively simple metal borates (e.g., vonsenite), to chemically complex borosilicates (e.g., prismatine), to a relatively rare borosilicate-carbonate (e.g., harkerite). Some are of primary igneous origin, while others are formed by a variety of prograde and retrograde metamorphic processes or by metasomatic / hydrothermal processes. Most of the boron minerals are formed within, or adjacent to, metasedimentary lithologies that surround the anorthositic massifs of the central Adirondacks. The metasedimentary rocks are thought to be the source of most of the boron, although additional boron isotope studies are needed to conﬁrm this and to constrain the mechanisms of the formation of these unusual minerals.


Introduction
Boron is an unusual element that is essential for life [1] and has many important technical applications, from rocket-fuel igniter to antiseptic eye drops. Because of its small ionic radius, boron is an element not found in most of the common rock-forming minerals, and few geologists are familiar with the distribution of boron in the Earth, or how boron behaves in geological processes. Because most borate compounds are water-soluble, borate minerals are most common in evaporite deposits and in clay-bearing sediments [2]. In metamorphic and igneous rocks, most boron is incorporated into tourmaline because of its stability over a wide range of pressures, temperatures, and bulk rock compositions [3]. In metamorphic rocks, other boron-bearing minerals are uncommon and form only in Table 1. List of boron-bearing minerals reported from northern New York, along with their chemical formulas and locations. Map # refers to location number on Figure 1.  9, x 4 of 31 [11,12] (Figure 1). The Adirondack Highlands are the southernmost extension of the Mesoproterozoic Grenville Province, a region underlain by granulite facies meta-igneous and meta-sedimentary rocks. The Highlands were multiply deformed during two major orogenic events: The Shawinigan Orogeny (~1165 Ma), and the Ottawan Phase of the Grenville Orogeny (~1050 Ma) [13]. Peak metamorphism in the Highlands occurred during the Ottawan Phase of the Grenville Orogeny. Approximately half of the investigated boron mineral occurrences are within the Adirondack Highlands, some hosted by meta-sedimentary lithologies, and others by igneous or meta-igneous lithologies. The Adirondack Lowlands are characterized by amphibolite facies, supracrustal rocks of the Grenville Supergroup that were deformed and metamorphosed during the Shawinigan Orogeny ( Figure 1) [14]. The Lowlands do not display features of the younger Ottawan Orogenic Phase, and it has been suggested that they are part of an extensive orogenic lid encompassing much of the southeastern edge of the Grenville Province [15]. Approximately half of the investigated boron mineral occurrences are within, or adjacent to, the Adirondack Lowlands, and all are hosted by metasedimentary lithologies.  The Adirondack Mountains in New York are divided into the Adirondack Highlands and Adirondack Lowlands by a zone of deformation known as the Colton-Carthage shear zone (CCsz) [11,12] (Figure 1). The Adirondack Highlands are the southernmost extension of the Mesoproterozoic Grenville Province, a region underlain by granulite facies meta-igneous and meta-sedimentary rocks. The Highlands were multiply deformed during two major orogenic events: The Shawinigan Orogeny (~1165 Ma), and the Ottawan Phase of the Grenville Orogeny (~1050 Ma) [13]. Peak metamorphism in the Highlands occurred during the Ottawan Phase of the Grenville Orogeny. Approximately half of the investigated boron mineral occurrences are within the Adirondack Highlands, some hosted by meta-sedimentary lithologies, and others by igneous or meta-igneous lithologies.

Sample ID
The Adirondack Lowlands are characterized by amphibolite facies, supracrustal rocks of the Grenville Supergroup that were deformed and metamorphosed during the Shawinigan Orogeny ( Figure 1) [14]. The Lowlands do not display features of the younger Ottawan Orogenic Phase, and it has been suggested that they are part of an extensive orogenic lid encompassing much of the southeastern edge of the Grenville Province [15]. Approximately half of the investigated boron mineral occurrences are within, or adjacent to, the Adirondack Lowlands, and all are hosted by meta-sedimentary lithologies.

Danburite History and Geologic Setting
Danburite is a calcium borosilicate associated with skarns and high-grade metamorphosed calc-silicates. Fairly large crystals (up to 10 cm long) were first collected in the town of Russell in the Adirondack Lowlands by Chester D. Nims in the late 1870s, and identified by Brush and Dana [16] (Figure 2). Good descriptions and overviews of the mineral assemblage at the Russell danburite occurrence can be found in Clark [17] and in Chamberlain, Lupulescu, Bailey and Carlin [7]. Minor danburite was reported to occur at the McLear pegmatite in the town of Dekalb [18], although this has not been confirmed by more recent studies [19,20]. A third locality was discovered in 2014 in the town of Macomb [21].  Stephen Nightingale photo; previously described in [7]. Stephen Nightingale photo; previously described in [7].
The recently discovered danburite occurrence in the town of Macomb is approximately 25 km northwest of the Russell locality. Here, a small (~5 m long) zone of danburite mineralization occurs along the contact of a small pegmatite intrusion with the Grenville marble [21]. Crystals of danburite up to 12.5 cm long are associated with albite, calcite, diopside, dravite, marialite, quartz, phlogopite, and minor tremolite, graphite, pyrite, titanite, and zircon [21]. While mineralogically similar to the classic site in Russell, here, the danburite is clearly part of a skarn formed by the intrusion of a small granitic pegmatite. The age of the Macomb pegmatite and skarn formation has recently been dated at 1168 ± 2.8 Ma [23].

Danburite Properties
Despite many of the crystals having rough and rounded crystal faces, Brush and Dana did a detailed crystallographic analysis of the danburite crystals from Russell. The crystals tend to be elongated, with prominent {110} and {120} rhombic prisms, with a total of 23 distinct crystal forms identified [16]. The danburite crystals from Macomb exhibit a similar morphology but tend to be less elongated and flattened perpendicular to [100] [21].
Danburite crystals from the original locality in Russell, NY, have been analyzed by wet chemistry and by electron microprobe (Table 2). Both analyses revealed that the crystals are relatively pure, with only minor amounts of Al, Fe, and Mg. The relatively high concentration of Al 2 O 3 reported in the wet chemical analysis was likely due to the impurities included in the bulk sample, although limited substitution of Al 3+ and H + for Si 4+ is possible [24].
LA-ICP-MS analysis revealed low concentrations of almost all trace elements in both the Russell and Macomb danburites, with the exception of Sr (826 and 713 ppm, respectively) ( Table 3). Both danburites also have a strong preference for incorporating light REE and exhibit steep chondrite-normalized profiles ( Figure 3). Compared to danburites from other world localities, the Adirondack danburites have overall REE concentrations lower than the danburites from Tanzania or Vietnam, but significantly higher than the danburites from Charcas, Mexico ( Figure 3). Table 2. Major element analyses of boron-bearing minerals from the Adirondacks (in weight percent). All averages of three spot analyses by electron microprobe at RPI with the exception of: (a) Wet chemical analysis of Russell danburite [16]; (b) electron microprobe analysis of grandidierite from Russell [25]; (c) electron microprobe and ion microprobe analysis of harkerite [26]; (d) average of two electron microprobe and ion microprobe analysis of prismatine sample MR-99-11 from Moose River [27], (e) average of two wet chemical analysis of Johnsburg serendibite [28], (f ) average of two electron microprobe analysis of Russell serendibite [25], (g) electron microprobe analysis of sinhalite from Johnsburg [29], (h) wet chemical analysis of Jayville vonsenite [30], and (i) electron microprobe analysis of Edwards warwickite [31]. EMP = electron microprobe; SIMS = secondary ion mass spectrometry; nd = not detected; blank cells = not analyzed; numbers in blue italics are calculated by analytical difference; the analytical difference in datolite partitioned between H 2 O and B 2 O 3 assuming one mole (OH) per formula unit. For all EMP analyses, total iron is reported as either all ferric (Fe 2 O 3 T ) or all ferrous iron (FeO *); for the two wet chemical analyses, iron is reported as analyzed.     Stephen Nightingale photo; previously described in [7]. Raman spectra on danburite from the classic locality in Russell and from the recently discovered locality in Macomb are similar, and most of the peaks correspond to those observed in gem-quality danburite from Charcas, Mexico ( Figure 4); the lack of a strong peak at ~250 cm −1 in the Macomb danburite is a notable difference that might be due to crystal orientation. The Raman peaks observed in both samples are consistent with those observed by Best et al. [33], with peaks between 800 and 1100 cm −1 assigned to Si-O-B and B-O-B bond stretching modes, the large peak around 620 cm −1 assigned to B-O-Si bond bending, and the 120 to 350 cm −1 peaks largely assigned to Ca translations and rotations of B2O and Si2O7 structural units, respectively. As noted by Best [33], assignment of bands to stretching, bending, and lattice modes in danburite is problematic because of the framework structure, and that breaking the danburite lattice into [Si2O7] 6− , [B2O] 4+ and Ca 2+ ions is physically unrealistic, yet it results in good predictions of the numbers of bands for each symmetry species. Raman spectra on danburite from the classic locality in Russell and from the recently discovered locality in Macomb are similar, and most of the peaks correspond to those observed in gem-quality danburite from Charcas, Mexico ( Figure 4); the lack of a strong peak at~250 cm −1 in the Macomb danburite is a notable difference that might be due to crystal orientation. The Raman peaks observed in both samples are consistent with those observed by Best et al. [33], with peaks between 800 and 1100 cm −1 assigned to Si-O-B and B-O-B bond stretching modes, the large peak around 620 cm −1 assigned to B-O-Si bond bending, and the 120 to 350 cm −1 peaks largely assigned to Ca translations and rotations of B 2 O and Si 2 O 7 structural units, respectively. As noted by Best [33], assignment of bands to stretching, bending, and lattice modes in danburite is problematic because of the framework structure, and that breaking the danburite lattice into [Si 2 O 7 ] 6− , [B 2 O] 4+ and Ca 2+ ions is physically unrealistic, yet it results in good predictions of the numbers of bands for each symmetry species.    [34]. All spectra collected on unoriented samples using a 532 nm laser and background corrected.

Datolite History and Geologic Setting
Datolite is a calcium borosilicate commonly associated with zeolites in hydrothermally altered mafic volcanic rocks. While beautiful, well-formed, translucent crystals of datolite have been collected from southern New York and New Jersey for over 200 years [35], well-formed crystals are rare in the Adirondack region, even though datolite has been reported at six different locations ( Figure 1).
Datolite was first reported at Schroon Lake in the eastern Adirondacks, where it was found as microscopic crystals in cavities in a metagabbro along with crystals of chabazite [36]. Datolite also occurs in association with the danburite at Russell and Macomb (described above), but only as fine coatings on, or fracture fillings within, the earlier danburite crystals [3,7]. Datolite was also reported  [34]. All spectra collected on unoriented samples using a 532 nm laser and background corrected.

Datolite History and Geologic Setting
Datolite is a calcium borosilicate commonly associated with zeolites in hydrothermally altered mafic volcanic rocks. While beautiful, well-formed, translucent crystals of datolite have been collected from southern New York and New Jersey for over 200 years [35], well-formed crystals are rare in the Adirondack region, even though datolite has been reported at six different locations ( Figure 1).
Datolite was first reported at Schroon Lake in the eastern Adirondacks, where it was found as microscopic crystals in cavities in a metagabbro along with crystals of chabazite [36]. Datolite also occurs in association with the danburite at Russell and Macomb (described above), but only as fine coatings on, or fracture fillings within, the earlier danburite crystals [3,7]. Datolite was also reported to occur at the gem diopside locality in Dekalb [37], but more recent studies have failed to confirm its presence at this site [38]. It was also reported as a rare mineral at the Woodcock mine in the Fowler talc belt [39], but this occurrence has similarly not been confirmed.
In all of the Adirondack occurrences, datolite is a late-stage, low-temperature, hydrothermal mineral. This is supported by phase equilibria in the system CaO-B 2 O 3 -SiO 2 -H 2 O-CO 2 , which indicates that at relatively low temperatures, datolite is favored over danburite in the presence of H 2 O-rich fluids [3]. At all of the localities in the Adirondacks, datolite is a secondary mineral forming from the breakdown of preexisting high-grade borosilicate minerals (e.g., danburite and/or tourmaline). The source of the boron for the datolite at the Valentine mine is unclear since no boron-bearing minerals have been identified in the any of the pre-existing skarn lithologies [40,41].
mineral. This is supported by phase equilibria in the system CaO-B2O3-SiO2-H2O-CO2, which indicates that at relatively low temperatures, datolite is favored over danburite in the presence of H2O-rich fluids [3]. At all of the localities in the Adirondacks, datolite is a secondary mineral forming from the breakdown of preexisting high-grade borosilicate minerals (e.g., danburite and/or tourmaline). The source of the boron for the datolite at the Valentine mine is unclear since no boronbearing minerals have been identified in the any of the pre-existing skarn lithologies [40,41].

Datolite Properties
Datolite from most of the Adirondack localities is extremely fine-grained and occurs as overgrowths on earlier calc-silicate minerals. At the Valentine wollastonite mine, the crystals are larger (up to 1 cm), typically transparent, pale greenish-yellow, wedge-shaped, and striated [40].
Chemically, datolite from the Valentine mine in Harrisville is essentially stochiometric, with only minor impurities of iron and potassium ( Table 2). It contains extremely low concentrations (<1 ppm) of most trace elements, with the exception of Sr and the light REE (3-18 ppm). Overall, REE concentrations are similar to those observed in datolites from the altered basalts of northern NJ, although they lack the positive europium anomaly; REE concentrations are significantly higher than those seen in the altered ophiolitic rocks of the northern Apennines in Italy ( Figure 6).
Raman spectra on datolite from the Valentine mine are nearly identical to spectra of datolite from the calc-silicate skarn at Charcas, Mexico ( Figure 7). Frost et al. [42] attributed the peaks at ~917 cm −1 and 985 cm −1 to symmetric and antisymmetric B-O stretching, respectively, and the peaks at

Datolite Properties
Datolite from most of the Adirondack localities is extremely fine-grained and occurs as overgrowths on earlier calc-silicate minerals. At the Valentine wollastonite mine, the crystals are larger (up to 1 cm), typically transparent, pale greenish-yellow, wedge-shaped, and striated [40].
Chemically, datolite from the Valentine mine in Harrisville is essentially stochiometric, with only minor impurities of iron and potassium ( Table 2). It contains extremely low concentrations (<1 ppm) of most trace elements, with the exception of Sr and the light REE (3-18 ppm). Overall, REE concentrations are similar to those observed in datolites from the altered basalts of northern NJ, although they lack the positive europium anomaly; REE concentrations are significantly higher than those seen in the altered ophiolitic rocks of the northern Apennines in Italy ( Figure 6).
Raman spectra on datolite from the Valentine mine are nearly identical to spectra of datolite from the calc-silicate skarn at Charcas, Mexico (Figure 7). Frost et al. [42] attributed the peaks at~917 cm −1 and 985 cm −1 to symmetric and antisymmetric B-O stretching, respectively, and the peaks at~1080 cm −1 and 1170 cm −1 to symmetric and antisymmetric stretching of tetrahedral Si-O bonds, respectively. The large peak around 700 cm −1 is assigned to symmetric stretching of tetrahedral B-O bonds and the large peak at~165 cm −1 is suggested to be an O-Ca-O bending mode.
~1080 cm −1 and ~1170 cm −1 to symmetric and antisymmetric stretching of tetrahedral Si-O bonds, respectively. The large peak around 700 cm −1 is assigned to symmetric stretching of tetrahedral B-O bonds and the large peak at ~165 cm −1 is suggested to be an O-Ca-O bending mode.   [34]. Both spectra collected on unoriented samples using a 532 nm laser, and background corrected.

Dumortierite History and Geologic Setting
Dumortierite is an uncommon, Al-rich, borosilicate typically found in granitic pegmatites or in high-grade metapelitic rocks. Nice specimens of dumortierite have been known from southern New Figure 6. Chondrite-normalized rare earth element profiles of datolite. Harrisville Valentine property datolite profile is an average of three spot analyses (this study). Italy datolite profile is an average of seven analyses from reference [43]; Patterson, NJ analysis from reference [44]. ~1080 cm −1 and ~1170 cm −1 to symmetric and antisymmetric stretching of tetrahedral Si-O bonds, respectively. The large peak around 700 cm −1 is assigned to symmetric stretching of tetrahedral B-O bonds and the large peak at ~165 cm −1 is suggested to be an O-Ca-O bending mode.   [34]. Both spectra collected on unoriented samples using a 532 nm laser, and background corrected.

Dumortierite History and Geologic Setting
Dumortierite is an uncommon, Al-rich, borosilicate typically found in granitic pegmatites or in high-grade metapelitic rocks. Nice specimens of dumortierite have been known from southern New  [34]. Both spectra collected on unoriented samples using a 532 nm laser, and background corrected.

Dumortierite History and Geologic Setting
Dumortierite is an uncommon, Al-rich, borosilicate typically found in granitic pegmatites or in high-grade metapelitic rocks. Nice specimens of dumortierite have been known from southern New York pegmatites for over 100 years [45], but only recently has dumortierite been reported from pegmatites in the Adirondacks [46,47].
In the eastern Adirondacks, small (<2 mm long) needles of blue dumortierite ( Figure 8) were found at the margin of the Batchellerville pegmatite, where it is in contact with a biotite gneiss. The dumortierite is associated with quartz, albite, and microcline (present as anti-perthite lamellae) and minor apatite [46]. pegmatites in the Adirondacks [46,47].
In the eastern Adirondacks, small (<2 mm long) needles of blue dumortierite ( Figure 8) were found at the margin of the Batchellerville pegmatite, where it is in contact with a biotite gneiss. The dumortierite is associated with quartz, albite, and microcline (present as anti-perthite lamellae) and minor apatite [46].
At the Benson Iron Mines in Star Lake, dumortierite also occurs as small needles at the contact of small pegmatitic veins intruding a mafic gneiss. The purple-blue, acicular crystals (up to 3 mm long), are associated with quartz and sillimanite. In some pegmatite bodies, dumortierite is included within gem-quality feldspar and has a narrow tourmaline envelope [47].
In the central Adirondacks, dumortierite has also been reported from a small granitic pegmatite on Ledge mountain, northwest of Indian Lake, where it is associated with quartz and chlorite [48].

Dumortierite Properties
At all three localities in the Adirondacks, dumortierite occurs as relatively small, acicular, blue crystals along the margins of small granitic pegmatites. Major element compositions of dumortierite from Batchellerville ( Most trace element concentrations in dumortierites from the Benson Mines and Batchellerville are quite low (<10 ppm), and many, including most of the REE, are below detection limits (Table 3). Notable exceptions are the semi-metals As, Sb, and Bi, with concentrations up to 4000 ppm, and the high-field strength elements Ta, Nb, and Zr, with concentrations up to 200 ppm. Pieczka et al. reported [49,50] that Ta and Nb substitute for aluminum in the Al1 site of dumortierite as part of the solid solution with holtite, and As and Sb substitute for Si as seen in szklaryite.
A Raman spectrum on the Batchellerville dumortierite ( Figure 9) is a fairly good match to the Raman spectrum of dumortierite from Dehesa, CA, although notable differences in peak intensities At the Benson Iron Mines in Star Lake, dumortierite also occurs as small needles at the contact of small pegmatitic veins intruding a mafic gneiss. The purple-blue, acicular crystals (up to 3 mm long), are associated with quartz and sillimanite. In some pegmatite bodies, dumortierite is included within gem-quality feldspar and has a narrow tourmaline envelope [47].
In the central Adirondacks, dumortierite has also been reported from a small granitic pegmatite on Ledge mountain, northwest of Indian Lake, where it is associated with quartz and chlorite [48].

Dumortierite Properties
At all three localities in the Adirondacks, dumortierite occurs as relatively small, acicular, blue crystals along the margins of small granitic pegmatites. Major element compositions of dumortierite from Batchellerville ( Most trace element concentrations in dumortierites from the Benson Mines and Batchellerville are quite low (<10 ppm), and many, including most of the REE, are below detection limits (Table 3). Notable exceptions are the semi-metals As, Sb, and Bi, with concentrations up to 4000 ppm, and the high-field strength elements Ta, Nb, and Zr, with concentrations up to 200 ppm. Pieczka et al. reported [49,50] that Ta and Nb substitute for aluminum in the Al1 site of dumortierite as part of the solid solution with holtite, and As and Sb substitute for Si as seen in szklaryite.
A Raman spectrum on the Batchellerville dumortierite ( Figure 9) is a fairly good match to the Raman spectrum of dumortierite from Dehesa, CA, although notable differences in peak intensities and slight shifts in peak wavenumbers are seen. Differences in crystal orientation might explain these differences. and slight shifts in peak wavenumbers are seen. Differences in crystal orientation might explain these differences. Figure 9. Raman spectrum of dumortierite from Batchellerville, NY, showed in comparison to that of dumortierite from Dehesa, CA [34]. Both spectra collected on unoriented samples using a 532 nm laser, and background corrected.
In the Adirondacks, grandidierite is found only at two localities; Johnsburg in the Adirondack Highlands, and Russell in the Adirondack Lowlands ( Figure 1). In both, the grandidierite occurs as small, anhedral grains apparently forming from the breakdown of serendibite (described below) by the reaction [29]: serendibite + diopside + Na2O + H2O + CO2 = grandidierite + pargasite + calcite + B2O3 Conditions of grandidierite formation are interpreted to have been lower granulite facies at Johnsburg, and upper amphibolite facies at Russell [25].

Grandidierite Properties
Grandidierite is pleochroic blue-green in a thin section and occurs as irregular patchy grains within, or surrounding, the larger serendibite crystals [29]. The only chemical analysis of grandidierite from the Adirondacks [25] indicates that it is very Mg-rich and Fe-poor (Table 2). Samples for additional analysis were unable to be located.

Harkerite History and Geologic Setting
Harkerite is a rare borosilicate carbonate typically found in high-temperature, low pressure, calcsilicate skarns [3,59]. Harkerite was first identified at Cascade Slide in the Adirondack Highlands by Figure 9. Raman spectrum of dumortierite from Batchellerville, NY, showed in comparison to that of dumortierite from Dehesa, CA [34]. Both spectra collected on unoriented samples using a 532 nm laser, and background corrected.
In the Adirondacks, grandidierite is found only at two localities; Johnsburg in the Adirondack Highlands, and Russell in the Adirondack Lowlands ( Figure 1). In both, the grandidierite occurs as small, anhedral grains apparently forming from the breakdown of serendibite (described below) by the reaction [29]: Conditions of grandidierite formation are interpreted to have been lower granulite facies at Johnsburg, and upper amphibolite facies at Russell [25].

Grandidierite Properties
Grandidierite is pleochroic blue-green in a thin section and occurs as irregular patchy grains within, or surrounding, the larger serendibite crystals [29]. The only chemical analysis of grandidierite from the Adirondacks [25] indicates that it is very Mg-rich and Fe-poor (Table 2). Samples for additional analysis were unable to be located.

Harkerite History and Geologic Setting
Harkerite is a rare borosilicate carbonate typically found in high-temperature, low pressure, calc-silicate skarns [3,59]. Harkerite was first identified at Cascade Slide in the Adirondack Highlands by Jaffe, reported by Baillieul in 1976 [60], and confirmed in subsequent studies [26,61]. Material suitable for additional analysis was unable to be located.
Cascade Slide is an unusual occurrence of medium-to coarse-grained marble in the Adirondack Highlands surrounded by anorthosite (Figure 1). Baillieul noted that the harkerite occurred as indistinct, opaque, white grains up to 3 mm in a calc-silicate marble, where it commonly formed irregular rims around diopside and monticellite grains; it could be easily identified by its red-orange fluorescence under short-wave ultraviolet radiation [60]. Commonly associated minerals include: Calcite, monticellite, diopside, and spinel; less commonly observed minerals include forsterite, garnet, magnetite, and barite [26].
The occurrence of harkerite at Cascade Slide is unusual in that it occurs in a region of granulite facies metamorphism, where peak metamorphic conditions are thought to have been 7.4 ± 1 kbar and 750 ± 30 • C [61]. Possible explanations for the presence of harkerite in high-pressure metamorphic rocks include: 1) Stabilization at high pressures due to extremely low CO 2 activities, or 2) localized preservation of earlier, low-pressure mineral assemblages [3]. Recent oxygen isotope and geochronology studies in the Adirondacks support the latter interpretation, with relatively shallow emplacement of the large anorthosite massifs resulting in localized skarn formation at~1155 Ma, followed by high-pressure granulite facies metamorphism at~1050 Ma [62,63]. Harkerite may have been preserved at these high pressures due to the near-absence of a fluid phase during subsequent granulite facies metamorphism [26].

Harkerite Properties
The harkerite at Cascade Slide occurs as small (typically < 3 mm), irregular patches in a medium-grained, monticellite-diopside-marble; usually with blue calcite [26,60]. Optically, the harkerite grains exhibit very low, first-order interference colors, and in some instances, fine polysynthetic twinning, which may have been introduced during the transformation from an isometric to a trigonal structure [26].
Powder X-ray diffraction [60] and Fourier transform infrared (FTIR) spectroscopy both yield patterns nearly identical to those on harkerite from the type locality in Skye, UK [26].
Chemical analyses of harkerite grains from Cascade slide ( Table 2) have higher silicon, and lower boron contents than harkerite from the type locality, presumably due to the substitution (BO 3 ) 4 = AlSi 4 O 15 (OH) [26]. While no trace element analysis has been performed on the Cascade Slide harkerite, on the basis of charge balance and site occupancy considerations, Grew et al. suspect significant substitution of Sr, Y, and/or REE [26]. These minerals are described here in the same section because they vary only in the amount of boron in the crystal structure. The two minerals, kornerupine, and prismatine form the kornerupine mineral group, which contains 0.0 to 1.0 formula units B (per 21.5 oxygens) [64,65]. Kornerupine contains between 0.0 and 0.5 formula units B, whereas prismatine contains 0.5 to 1.0 formula units. Because boron is not commonly determined by electron microprobe methods, any specimen of the kornerupine mineral group where the B content is unknown should be considered "kornerupine" (sensu lato) [64].
In the Adirondacks, kornerupine is reported from the Warrensburg area in the southeast [66][67][68][69], and prismatine is reported from the Moose River area in the west [27] (Figure 1, locations 14, 15, and 16). Unlike the prismatine located in the Moose River area, the boron content of the Warrensburg locality has not been reported, thus it is referred to as kornerupine in this report consistent with the original publications of Farrar [66][67][68][69].
Kornerupine from the Warrensburg area occurs in Al-rich ultramafic rocks (comprising forsterite, bronzite, tschermakite, spinel, and phlogopite) associated with an anorthosite sill [67]. The kornerupine occurs as a late phase along with pyrope, corundum, and sapphirine [67]. Prismatine from the Moose River area, in the western Adirondacks, forms spectacularly developed, dark green, euhedral crystals ( Figure 10) measuring up to 10 cm or more along the c-axis. In surface exposures, prismatine forms radiating sprays in coarse-grained feldspathic lenses that are generally parallel to gneissic foliation. In these lenses, the prismatine is arranged randomly, but the longest and best-developed crystals are formed parallel to the foliation plane. The euhedral shape and the random arrangement are inferred to be the result of crystallization from a melt [27]. A proposed melt forming reaction is [27]: kornerupine occurs as a late phase along with pyrope, corundum, and sapphirine [67]. Prismatine from the Moose River area, in the western Adirondacks, forms spectacularly developed, dark green, euhedral crystals ( Figure 10) measuring up to 10 cm or more along the c-axis. In surface exposures, prismatine forms radiating sprays in coarse-grained feldspathic lenses that are generally parallel to gneissic foliation. In these lenses, the prismatine is arranged randomly, but the longest and bestdeveloped crystals are formed parallel to the foliation plane. The euhedral shape and the random arrangement are inferred to be the result of crystallization from a melt [27]. A proposed melt forming reaction is [27]:

tourmaline + sillimanite + biotite + cordierite → prismatine + rutile + melt
Here, the prismatine (and rutile) are the peritectic phases. Figure 10 (bottom) shows prismatine surrounding a grain of hercynite, suggesting that hercynite may have been a reactant phase as well. Figure 11 shows some of the abundant rutile generated by the above reaction. Interestingly, the rutile shows what appears to be exsolution lamellae of ilmenite. Peak metamorphic conditions in this region are estimated to have reached ~850 ± 20 °C and 6.0 ± 0.6 kbar [27,70].  Here, the prismatine (and rutile) are the peritectic phases. Figure 10 (bottom) shows prismatine surrounding a grain of hercynite, suggesting that hercynite may have been a reactant phase as well. Figure 11 shows some of the abundant rutile generated by the above reaction. Interestingly, the rutile shows what appears to be exsolution lamellae of ilmenite. Peak metamorphic conditions in this region are estimated to have reached~850 ± 20 • C and 6.0 ± 0.6 kbar [27,70].

Kornerupine/Prismatine Properties
Crystals of the kornerupine-prismatine series are all orthorhombic, with space group Cmcm [71]. The crystal structure is complex, with three tetrahedral sites (T(1) through T(3)), five distinct octahedral sites (M(1) through M(5)), and one 8-coordination, distorted, cubic site (X); boron, when present, is completely ordered in the T(3) site [71]. As its name implies, prismatine tends to form highly prismatic grains with the {110} form dominating in euhedral specimens [64]. Prismatine from the Moose River area is no exception as prismatic faces parallel to the c-axis are well developed. Calculated interfacial angles between the {110} prism faces are about 81 • and 99 • based on unit cell dimensions of a, b listed in Table 2 of [64]. Significantly, it was these interfacial angles that first hinted that the elongated, dark-colored grains were not an amphibole (56 • and 124 • ) or a pyroxene (87 • and 93 • ). The identification as prismatine was later determined by powder X-ray diffraction, electron microprobe, and SIMS analysis [27]. Table 2 lists two electron microprobe analyses of prismatine, one is an average of two analysis from Table 3 (sample MR- Trace element data for the Moose River prismatine are listed in Table 3. The prismatine is relatively enriched in first row transition elements Sc, V, Cr, Co, Ni, Zn, Ga. These cations are inferred to occupy the five (6-fold) M sites and possibly the one (8-fold) X site in prismatine [71]. Rare earth element and Y concentrations are generally low (and below detection limits for Sm and Eu), but the prismatine is relatively enriched in the heavy rare earth elements (HREE), as shown in Figure 12. Because of their relatively large ionic radius, these elements are inferred to occupy only the single (8-fold) X site in prismatine [71]. This HREE enrichment (and light REE exclusion) in prismatine ( Figure 12) is similar to that of garnet, which frequently incorporates HREE into its three (8-fold) X sites. A number of substitution vectors for Y and REE have been proposed for garnet [72], and we suspect a similar number to operate in prismatine. However, the total amount of REE in prismatine is likely to be low as it has only one 8-fold site per 21.5 oxygens [64,71] compared to garnet's three 8-fold sites per 12 oxygens. occur at 326, 333, 401, 450, 515, 707, 762, 802, 882, 978 and 1015 cm −1 . All of the peak positions that are >700 cm −1 falls with the range of values listed in Table 1 of [73]. Frost et al. [74], attributed the peaks between 925 and 1085 cm -1 in kornerupine to Si-O-Si stretching vibrations, and the peaks they observed at 923 and 947 cm −1 to symmetrical stretching vibrations of trigonal boron. This assignment to stretching vibrations of trigonal boron is, however, problematic considering that detailed studies of the crystal chemistry of kornerupine and prismatine have shown that boron is completely ordered at the tetrahedral T(3) site [65,71]. In addition, we did not observe any distinct peaks at these wavenumbers in the Moose River prismatine. The pairs of strong peaks at ~965 and ~1010 cm −1 , and ~700 and ~750 cm −1 are characteristic of kornerupine and prismatine regardless of boron content [73]. Some peak positions are shifted slightly compared to those of the Sri Lankan sample ( Figure 13) and to those listed in Table 1 of [73], which are attributed to slight differences in major element chemistry. Variation in peak intensity is attributed to crystal orientation relative to the incident laser. Significantly, the strong peaks at 802 and 882 cm −1 confirm the presence of boron [73] in the Moose River prismatine.   Table 1 of [73]. Frost et al. [74], attributed the peaks between 925 and 1085 cm -1 in kornerupine to Si-O-Si stretching vibrations, and the peaks they observed at 923 and 947 cm −1 to symmetrical stretching vibrations of trigonal boron. This assignment to stretching vibrations of trigonal boron is, however, problematic considering that detailed studies of the crystal chemistry of kornerupine and prismatine have shown that boron is completely ordered at the tetrahedral T(3) site [65,71]. In addition, we did not observe any distinct peaks at these wavenumbers in the Moose River prismatine. The pairs of strong peaks at~965 and~1010 cm −1 , and~700 and 750 cm −1 are characteristic of kornerupine and prismatine regardless of boron content [73]. Some peak positions are shifted slightly compared to those of the Sri Lankan sample ( Figure 13) and to those listed in Table 1 of [73], which are attributed to slight differences in major element chemistry. Variation in peak intensity is attributed to crystal orientation relative to the incident laser. Significantly, the strong peaks at 802 and 882 cm −1 confirm the presence of boron [73] in the Moose River prismatine.  . Raman spectrum of prismatine from Moose River, NY, shown in comparison to that of kornerupine from Sri Lanka [34]. Both spectra collected on unoriented samples using a 532 nm laser, and background corrected.
rutile w/ ilmenite zircon Figure 13. Raman spectrum of prismatine from Moose River, NY, shown in comparison to that of kornerupine from Sri Lanka [34]. Both spectra collected on unoriented samples using a 532 nm laser, and background corrected.

Serendibite History and Geologic Setting
Serendibite is a rare borosilicate mineral with fewer than 20 distinct world localities [5]. The serendibite in the Adirondack Highlands near Johnsburg, NY, first reported in 1932, was the second recognized world locality [28]. Serendibite was later found in the Adirondack Lowlands in a drill core of the St. Joe Resources Company in the town of Russell, NY [25]. Serendibite is characteristically found in upper amphibolite to granulite facies, calc-silicate skarns [3,25].
The serendibite at Johnsburg is blue to gray-blue and occurs as massive, granular aggregates in small (10s cm wide) pods and lenses interpreted to be a skarn that formed along the contact of a potassium feldspar-rich meta-igneous lithology and a medium-grained, dolomite-bearing marble [29]. Major phases closely associated with the serendibite are diopside, phlogopite, scapolite, plagioclase feldspar, and tremolite [28]. Other phases noted by Larsen and Schaller [28] include orthoclase, tourmaline, spinel, chlorite, serpentine, sericite, and talc. Grew et al. [29] identified pargasite, sinhalite, grandidierite, and borian sapphirine; additional phases we identified by SEM/EDS include zircon, thorianite, and barite.
The only other known occurrence of serendibite in the Adirondacks was encountered in a drill core in the town of Russell in the Adirondack Lowlands. A serendibite-diopside rock occurred over a 13-20 cm interval at a depth of 17.7 m, in drill hole 1872, of the St. Joe Resources Company [25].
Here the deep blue serendibite is associated with apatite, calcite, pargasite, and fine-grained, secondary phyllosilicates (sericite and/or chlorite?); less common are scapolite, tourmaline, grandidierite, phlogopite, sinhalite(?), and spinel [25]. Similar to the serendibite at Johnsburg, grains of up to 1 cm are usually overgrown and replaced by multiple phases [25]. Grew et al. [25] proposed a three-stage history for the Russell serendibite lithology: (1) A primary metamorphic assemblage of serendibite + diopside ± scapolite ± apatite; (2) secondary assemblages of serendibite with tourmaline, grandidierite, pargasite, spinel, ± phlogopite; and (3) a late replacement of many phases by fine-grained phyllosilicates. Inferred conditions for the formation of serendibite at Russell are 660-750 • C and 6.7-7.4 kbar, slightly lower than the granulite facies conditions at Johnsburg [25]. The lack of any spatially associated igneous/meta-igneous lithology is also a notable difference with the Johnsburg locality; here the serendibite appears to have formed directly from high-grade metamorphism of boron-rich calcareous sediments.
Serendibite grains at Johnsburg are up to 1 cm in diameter, anhedral, and occasionally exhibit symplectic intergrowths with diopside [29]. Many grains are rimmed by tourmaline (dravite), scapolite, phlogopite, and/or calcite ( Figure 14). Less common are rims or overgrowths of pargasite, grandidierite, sinhalite, and/or borian sapphirine [29]. According to Grew [3], the equilibrium mineral assemblage at Johnsburg was serendibite + diopside + phlogopite + scapolite + sinhalite, which presumably formed under the peak metamorphic conditions in the region of 720-740 °C, and 6.5-8 kbar [75]. Most of the complex overgrowths are interpreted to be retrograde breakdown products of the primary serendibite [29]. The only other known occurrence of serendibite in the Adirondacks was encountered in a drill core in the town of Russell in the Adirondack Lowlands. A serendibite-diopside rock occurred over a 13-20 cm interval at a depth of 17.7 m, in drill hole 1872, of the St. Joe Resources Company [25]. Here the deep blue serendibite is associated with apatite, calcite, pargasite, and fine-grained,

Serendibite Properties
In both Adirondack localities, serendibite occurs as anhedral, pale to deep blue grains in a granular calc-silicate lithology. In thin section, grains exhibit high positive relief, are very pale blue and faintly pleochroic, and display prominent polysynthetic twinning on {011}.
Chemically, the two Adirondack serendibites are very similar in composition (Table 2) and are relatively Mg and Na-rich, and Fe-poor compared to the serendibites from other localities [25]. Grew et al. [25] noted that much of the observed chemical variation in the Adirondack serendibites could be explained by either the Tschermaks substitution (Mg + Si = 2 Al), or the coupled substitution (Na + Si = Ca + Al). We report here the first trace element analyses of the Johnsburg serendibite (Table 3). Grains contain low concentrations of most trace elements, with the exception of Ga (99 ppm) and Y (59 ppm), both of which are likely substituting for Al in the five Al-dominant octahedral sites [76]. Rare earth element concentrations are also quite low, with concentrations around 10X chondrite, although with a slight preference for the heavy REE and a pronounced negative Eu anomaly ( Figure 12).
A Raman spectrum of the Johnsburg serendibite ( Figure 15) shows multiple broad, relatively low-intensity peaks that only weakly correspond to peaks observed in serendibite from Burma; additional analyses of multiple grains in known crystallographic orientation are needed to fully characterize the nature of bonding in the Johnsburg serendibite.
although with a slight preference for the heavy REE and a pronounced negative Eu anomaly ( Figure  12).
A Raman spectrum of the Johnsburg serendibite ( Figure 15) shows multiple broad, relatively low-intensity peaks that only weakly correspond to peaks observed in serendibite from Burma; additional analyses of multiple grains in known crystallographic orientation are needed to fully characterize the nature of bonding in the Johnsburg serendibite. Figure 15. Raman spectrum of serendibite from Johnsburg, NY, showed in comparison to that of serendibite from Mogok, Burma [34]. Both spectra collected on unoriented samples using a 532 nm laser, and background corrected.  [34]. Both spectra collected on unoriented samples using a 532 nm laser, and background corrected.

Sinhalite History and Geologic Setting
Sinhalite is a rare magnesium aluminum borate found in high-grade calc-silicate lithologies. It was first recognized as a mineral in 1952 [77], and shortly thereafter, it was identified in association with the Johnsburg serendibite (described above) [78]. It also has been tentatively identified in association with the serendibite from Russell, NY [25].
At Johnsburg, the sinhalite forms anhedral grains up to 1 cm. It is typically in contact with scapolite and/or diopside, and in places it is enclosed by serendibite or tourmaline [29]. It is part of the equilibrium skarn assemblage serendibite + diopside + phlogopite + scapolite + sinhalite that formed at granulite facies conditions of~720-740 • C, and 6.5-8 kbar [3,29].

Sinhalite Properties
The Johnsburg sinhalite has not been well-characterized, and material for additional analysis was unable to be located. Schaller and Hildebrand [78] reported some fundamental optical properties and powder X-ray diffraction data for the Johnsburg sinhalite, and Grew et al. [29] provided two electron microprobe analyses of the Johnsburg sinhalite (average of their analyses provided in Table 2).
Interestingly, because sinhalite is isostructural with forsterite [79], it has been suggested that a coupled solid solution mechanism of B + Al = Mg + Si may exist between the two minerals [78]. Grew, however, showed that B-bearing olivines contain little Al and argued against this mechanism [3]. Sinhalite appears to be a distinct borate mineral with little to no solid solution with the silicate olivine group. Its paragenetic relationship to the multiple phases in the Johnsburg serendibite-diopside skarn is not well-established. Stillwellite-(Ce) is an uncommon, rare-earth-element borosilicate typically found as a late-stage metasomatic phase in metamorphosed calcareous sediments [80], or as a late hydrothermal phase in alkaline intrusions [81,82]. In New York State, the only known occurrence of stillwellite-(Ce) is in the iron ore deposits of Mineville in the eastern Adirondack Highlands (Figure 1). It was first identified in 1979 in a sample collected from the "Old Bed" orebody in the Adirondack Mine of the Republic Steel Company; the sample was collected near a fault at the minus 2100-feet level in the mine [83]. The presence of stillwellite-(Ce) was confirmed on the basis of both X-ray diffraction and semi-quantitative spectrographic chemical analysis [83]. More recent chemical analyses have confirmed the presence of stillwellite-(Ce) at Mineville [84], but because of the lack of available in-situ samples with carefully documented textural and mineralogical associations, the conditions under which these grains formed is unclear. In addition, the source of B to form stillwellite-(Ce) in these magnetite ore bodies is not obvious because there are no spatially associated meta-carbonates or alkaline intrusions.

Stillwellite-(Ce) Properties
At Mineville, stillwellite-(Ce) occurs in association with fluorapatite and magnetite as 1 to 2 mm wide, tabular crystals with a waxy luster, and a pink to reddish color ( Figure 16). Backscatter electron images reveal that monazite often rims and fills fractures within the stillwellite-(Ce) grains and that many of the grains are inhomogeneous and variably altered. Because of this, obtaining consistent and accurate compositional data was challenging. After mounting and imaging many grains, a few homogeneous cores with relatively bright backscatter intensities yielded consistent and essentially stochiometric major element compositions by electron microprobe (reported in Table 2). Chemically, the stillwellite-(Ce) is essentially (REE)BSiO 5 , with only minor substitution of Ca and Th. Unfortunately, we were unable to analyze these same spots by LA-ICPMS, and, therefore, are unable to report accurate trace element data for the Mineville stillwellite-(Ce). However, preliminary LA-ICPMS data indicate that while stillwellite-(Ce) has a strong preference for the light REE, all of the REE are present in relatively high concentrations ( Figure 17). Y, Th, and U, which are presumably substituting for the REE, are also present in moderate to high concentrations (1000 s to 10,000 s ppm). Ga and the semi-metals Ge and As are also present in moderate concentrations (~1000 s ppm) and are presumably substituting for silicon.
The Raman spectrum for Mineville stillwellite-(Ce) is similar, but not identical, to that of stillwellite-(Ce) from Tajikstan ( Figure 18). The complete lack of a major peak at ~ 475 cm −1 and the presence of a strong peak at ~1025 cm −1 may be artifacts of orientation, but suggest there may also be significant differences in the crystal chemistry of the two samples. Unfortunately, we were unable to analyze these same spots by LA-ICPMS, and, therefore, are unable to report accurate trace element data for the Mineville stillwellite-(Ce). However, preliminary LA-ICPMS data indicate that while stillwellite-(Ce) has a strong preference for the light REE, all of the REE are present in relatively high concentrations ( Figure 17). Y, Th, and U, which are presumably substituting for the REE, are also present in moderate to high concentrations (1000 s to 10,000 s ppm). Ga and the semi-metals Ge and As are also present in moderate concentrations (~1000 s ppm) and are presumably substituting for silicon.
Ga and the semi-metals Ge and As are also present in moderate concentrations (~1000 s ppm) and are presumably substituting for silicon.
The Raman spectrum for Mineville stillwellite-(Ce) is similar, but not identical, to that of stillwellite-(Ce) from Tajikstan ( Figure 18). The complete lack of a major peak at ~ 475 cm −1 and the presence of a strong peak at ~1025 cm −1 may be artifacts of orientation, but suggest there may also be significant differences in the crystal chemistry of the two samples.  The Raman spectrum for Mineville stillwellite-(Ce) is similar, but not identical, to that of stillwellite-(Ce) from Tajikstan ( Figure 18). The complete lack of a major peak at~475 cm −1 and the presence of a strong peak at~1025 cm −1 may be artifacts of orientation, but suggest there may also be significant differences in the crystal chemistry of the two samples. Vonsenite is a relatively rare iron borate of the ludwigite-vonsenite series. In 1947, B. F. Leonard found a metallic mineral with unusual optical properties in the ore from a drill core at the Jayville Figure 18. Raman spectrum of stillwellite-(Ce) from Mineville, NY showed in comparison to that of stillwellite-(Ce) from Dara-i-Pioz, Tajikistan [34]. Both spectra collected on unoriented samples using a 532 nm laser, and background corrected.

Vonsenite History and Geologic Setting
Vonsenite is a relatively rare iron borate of the ludwigite-vonsenite series. In 1947, B. F. Leonard found a metallic mineral with unusual optical properties in the ore from a drill core at the Jayville iron deposit, and tentatively identified it as ilvaite [30,85]. In 1950, Henderson, from Princeton University, prepared the mineral for spectrographic analysis and X-ray diffraction and realized that the mineral was not ilvaite, but he was unable to identify it [30]. In 1951, Axelrod and Fletcher, from the U.S. Geological Survey, identified the mineral as vonsenite [30]. One specimen of vonsenite was also found at the Clifton iron deposit, approximately 20 km northeast of the Jayville deposit [30]. While the Jayville vonsenite was described in a subsequent U.S.G.S. report in 1964 [86], only two recent studies have been done on the ore-forming processes involved in generating the vonsenite-bearing rocks [87,88].
At Jayville, vonsenite occurs as fine-grained (0.1 to 2.0 mm) gray to black granular aggregates or stubby prismatic crystals up to 5.5 cm in length. It is primarily associated with magnetite, clinoamphibole (pargasite), and biotite ( Figure 19). Additional minerals reported in association with the vonsenite-magnetite ore include orthopyroxene, clinopyroxene, scapolite, and fluorite, and less commonly, quartz, zircon, chlorite, talc, titanite, hematite, goethite, pyrite, and chalcopyrite [30,87]. Hall, Johnson and Rosner [87] report vonsenite partially replacing magnetite in the ore body, which is laced throughout by thin veins of vonsenite. The magnetite-vonsenite ores at Jayville were originally interpreted as a pyrometasomatic skarn deposit, where lenses and bodies of calcareous sedimentary rocks were enclosed and metasomatized by granitic intrusions (now granitic gneisses) [30]. Johnson, Chapman, and Valder [88] argued for a similar origin, where the magnetite-vonsenite ore bodies were formed by metasomatic alteration of calc-silicate gneisses due to the intrusion of the Lyon Mountain granite during the Ottawan orogeny. Lupelescu et al. [89] reached a similar conclusion, and using U/Pb zircon geochronology, dated the intrusive and ore-forming event to ca. 1040 Ma. However, Hall, Johnson, and Rosner [87] argued for a more complex ore-forming process involving a multi-stage series of fluid infiltration events. They present evidence for vonsenite formation by a boron-rich metasomatic event 70-90 Ma after the peak of Ottawan metamorphism and granite emplacement, and at greenschist facies metamorphic conditions.

Vonsenite Properties
In hand specimens, vonsenite is black, submetallic, and difficult to distinguish from the associated magnetite. In transmitted light, vonsenite is opaque; in reflected light, it exhibits very strong pleochroism [30]. Prismatic crystals from Jayville exhibit the following crystal forms: {001}, The magnetite-vonsenite ores at Jayville were originally interpreted as a pyrometasomatic skarn deposit, where lenses and bodies of calcareous sedimentary rocks were enclosed and metasomatized by granitic intrusions (now granitic gneisses) [30]. Johnson, Chapman, and Valder [88] argued for a similar origin, where the magnetite-vonsenite ore bodies were formed by metasomatic alteration of calc-silicate gneisses due to the intrusion of the Lyon Mountain granite during the Ottawan orogeny. Lupelescu et al. [89] reached a similar conclusion, and using U/Pb zircon geochronology, dated the intrusive and ore-forming event to ca. 1040 Ma. However, Hall, Johnson, and Rosner [87] argued for a more complex ore-forming process involving a multi-stage series of fluid infiltration events. They present evidence for vonsenite formation by a boron-rich metasomatic event 70-90 Ma after the peak of Ottawan metamorphism and granite emplacement, and at greenschist facies metamorphic conditions.
Vonsenite is the Fe-rich end-member of the ludwigite group, an isostructural group of orthorhombic metal borates. While substitution of Mg 2+ , Mn 2+, and Ni 2+ for Fe 2+ can be extensive, the borate at Jayville is near end-member vonsenite ( Table 2). Spectrographic analysis of a bulk sample in the 1950s identified trace concentrations of: Sn, Pb, Zn, Ti, Cu, Cr, Zr, Ba, Ca, Ag, Co, and Ni [30]. Modern LA-ICPMS analysis of an unaltered, single crystal revealed significant amounts of Sn (1827 ppm), Zn (436 ppm), Cd (93 ppm), and Zr (52 ppm); all other trace elements were under 20 ppm, and the REE were all at concentrations well-below chondrite ( Table 3).
The Jayville vonsenite is only weakly Raman-active, yielding a relatively poor spectrum with three distinct peaks at~226, 290, and 409 cm −1 (Figure 20). Only two of these match peaks seen in vonsenite from Spain, and the relatively large, broad peak at~610 cm −1 in the Spanish vonsenite was not detected. Because the samples are compositionally very similar [91], the spectral differences may largely be due to differences in crystal orientation. The intense Raman peaks observed by Frost et al. [92] in vonsenite at 997 cm −1 and at 1059 cm −1 , which they attributed to B-O stretching vibrational modes, are not seen in either the Jayville or Spanish vonsenite samples. largely be due to differences in crystal orientation. The intense Raman peaks observed by Frost et al. [92] in vonsenite at 997 cm −1 and at 1059 cm −1 , which they attributed to B-O stretching vibrational modes, are not seen in either the Jayville or Spanish vonsenite samples. Figure 20. Raman spectrum of vonsenite from Jayville, NY, showed in comparison to that of vonsenite from the Monchi mine, Spain [34]. Both spectra collected on unoriented samples using a 532 nm laser, and background corrected.

Warwickite History and Geologic Setting
Warwickite is a rare Mg-Ti-Fe borate found in high-grade, Mg-rich marbles (as it is at its type locality in Warwick, NY) [93], or in unusual B-rich skarns [94]. In 2013, while studying samples from the Edwards mining district in the New York State Museum collection, one of the authors (Lupulescu) came across some small, bright green crystals that were unusual in the context of the associated mineral assemblage of anhydrite, calcite, dolomite, spinel, and pyrite [31]. These were analyzed by electron microprobe and found to be essentially Fe-free warwickite [31] (Table 1). Since that time, Lupulescu has found similar (although light brown in color) crystals in a sample from the Balmat Figure 20. Raman spectrum of vonsenite from Jayville, NY, showed in comparison to that of vonsenite from the Monchi mine, Spain [34]. Both spectra collected on unoriented samples using a 532 nm laser, and background corrected.

Warwickite History and Geologic Setting
Warwickite is a rare Mg-Ti-Fe borate found in high-grade, Mg-rich marbles (as it is at its type locality in Warwick, NY) [93], or in unusual B-rich skarns [94]. In 2013, while studying samples from