Next Article in Journal
Maximizing Economic Performance in the Mining Industry by Applying Bioleaching Technology for Extraction of Polymetallic Mineral Deposits
Next Article in Special Issue
Constraints from Geochemistry and Field Relationships for the Origin of Kornerupine-Bearing Gneiss from the Grenvillian New Jersey Highlands and Implications for the Source of Boron
Previous Article in Journal
Physico–Chemical Interaction between Clay Minerals and Albumin Protein according to the Type of Clay
Open AccessEditor’s ChoiceCommunication

The Atomic Arrangement of Cr-rich Tourmaline from the #1 Mine, Balmat, St. Lawrence County, New York, USA

1
Department of Geology, University of Vermont, Burlington, VT 05405, USA
2
New York State Museum, Research and Collections, 3140 CEC, Albany, NY 12230, USA
*
Author to whom correspondence should be addressed.
Minerals 2019, 9(7), 398; https://doi.org/10.3390/min9070398
Received: 16 May 2019 / Revised: 24 June 2019 / Accepted: 27 June 2019 / Published: 28 June 2019
(This article belongs to the Special Issue Minerals of the Southern Grenville Province)
Chromium-bearing tourmalines are rare. Chromium-rich tourmaline from the northwestern part of the Adirondack Mountains in the Adirondack Lowlands is among the most chromium-rich tourmalines found to date. The mineral, with >21.0 wt. % Cr2O3, is from the marble-hosted talc–tremolite–cummingtonite schist in the #1 mine in Balmat, St. Lawrence County, New York. The atomic arrangement of the sample (a = 16.0242(3) Å, c = 7.3002(2) Å) was refined to R1 = 0.0139. The composition, from chemical analyses and optimization of the formula, is X(Ca0.22Na0.69K0.01) Y(Cr3+1.68Mg0.80Ti0.13V0.06Mn0.02Fe0.02Li0.29) Z(Al3.11Cr3+1.18Mg1.70Fe0.01) T(Si5.93Al0.07) B3O27 OH3.99 F0.01. There has been extensive debate over the ordering of Cr3+ between the tourmaline Y and Z octahedral sites. Recent work has suggested that, at low concentrations (<~1.03 apfu), the substituent Cr3+ is ordered into the Y-site, whereas, at greater concentrations, the substituent is disordered over both octahedral sites. An analysis of nine recently published, high-precision structures of chromium-bearing tourmaline, in combination with the Adirondack tourmaline, suggests that structural changes to the Y-site at low concentrations of Cr3+ induce changes in the Z-site that make it more amenable to incorporation of the Cr3+ substituents by increasing <Z–O>. The bond lengths change to lower the bond-valence sum of Cr3+ in the Z-site of the chromium-dravite, making that site more amenable to the substituent. Calculations suggest that the Z-site begins to accept substituent Cr3+ when the bond valence sum of that ion in Z reduces to a value of ~3.36 valence units. View Full-Text
Keywords: tourmaline; chromium-dravite; Balmat mine; St. Lawrence County; New York tourmaline; chromium-dravite; Balmat mine; St. Lawrence County; New York
Show Figures

Figure 1

MDPI and ACS Style

Dannenberg, S.G.; Di Paolo, D.; Ehlers, A.M.; McCarthy, K.P.; Mancini, M.T.; Reuter, M.B.; Seth, D.M.; Song, Z.; Valladares, M.I.; Zhu, X.; Hughes, J.M.; Lupulescu, M.V. The Atomic Arrangement of Cr-rich Tourmaline from the #1 Mine, Balmat, St. Lawrence County, New York, USA. Minerals 2019, 9, 398. https://doi.org/10.3390/min9070398

AMA Style

Dannenberg SG, Di Paolo D, Ehlers AM, McCarthy KP, Mancini MT, Reuter MB, Seth DM, Song Z, Valladares MI, Zhu X, Hughes JM, Lupulescu MV. The Atomic Arrangement of Cr-rich Tourmaline from the #1 Mine, Balmat, St. Lawrence County, New York, USA. Minerals. 2019; 9(7):398. https://doi.org/10.3390/min9070398

Chicago/Turabian Style

Dannenberg, Steven G.; Di Paolo, Devany; Ehlers, Alix M.; McCarthy, Kyle P.; Mancini, Mark T.; Reuter, Matthew B.; Seth, Dennis M.; Song, Zihui; Valladares, Maria I.; Zhu, Xuanfu; Hughes, John M.; Lupulescu, Marian V. 2019. "The Atomic Arrangement of Cr-rich Tourmaline from the #1 Mine, Balmat, St. Lawrence County, New York, USA" Minerals 9, no. 7: 398. https://doi.org/10.3390/min9070398

Find Other Styles
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Search more from Scilit
 
Search
Back to TopTop