Hostname: page-component-848d4c4894-75dct Total loading time: 0 Render date: 2024-05-26T01:18:20.931Z Has data issue: false hasContentIssue false
  • English
  • Français

Kyawthuite, Bi3+Sb5+O4, a new gem mineral from Mogok, Burma (Myanmar)

Published online by Cambridge University Press:  02 January 2018

Anthony R. Kampf ,
George R. Rossman ,
Chi Ma  and
Peter A. Williams
Anthony R. Kampf*
Affiliation:
Mineral Sciences Department, Natural History Museum of Los Angeles County, 900 Exposition Blvd., Los Angeles, CA 90007, USA
George R. Rossman
Affiliation:
Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA
Chi Ma
Affiliation:
Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA
Peter A. Williams
Affiliation:
School of Science and Health, University of Western Sydney, Locked Bag 1797, Penrith NSW 2751, Australia
*
*E-mail: akampf@nhm.org
Get access Rights & Permissions [Opens in a new window]

Abstract

Kyawthuite, Bi3+Sb5+O4, is a new gem mineral found as a waterworn crystal in alluvium at Chaung-gyi-ah-le-ywa in the Chaung-gyi valley, near Mogok, Burma (Myanmar). Its description is based upon a single sample, which was faceted into a 1.61-carat gem.The composition suggests that the mineral formed in a pegmatite. Kyawthuite is monoclinic, space group I2/c, with unit cell dimensions a = 5.4624(4), b = 4.88519(17), c = 11.8520(8) Å, β = 101.195(7)°, V = 310.25(3) Å3and Z = 4. The colour is reddish orange and the streak is white. It is transparent with adamantine lustre. The Mohs hardness is 5½. Kyawthuite is brittle with a conchoidal fracture and three cleavages: {001} perfect, {110} and {110} good. The measured density is 8.256(5) g cm–3and the calculated density is 8.127 g cm–3. The mineral is optically biaxial with 2V = 90(2)°. The predicted indices of refraction are α = 2.194, β = 2.268, γ = 2.350. Pleochroism is imperceptible and the optical orientation is X = b; Y≈ c; Z ≈ a. Electron microprobe analyses, provided the empirical formula (Bi0.823+Sb0.183+)∑1.00(Sb0.995+Ta0.015+)∑1.00O4. The Raman spectrumis similar to that of synthetic Bi3+Sb5+O4. The infrared spectrum shows a trace amount of OH/H2O. The eight strongest powder X-ray diffraction lines are [dobs in Å(I)(hkl)]: 3.266(100)(112), 2.900(66)(112), 2.678(24)(200), 2.437(22)(020,114), 1.8663(21)(024), 1.8026(43)(116,220,204), 1.6264(23)(224,116) and 1.5288(28)(312,132). In the crystal structure of kyawthuite (R1 = 0.0269 for 593 reflections with Fo > 4σF), Sb5+O6 octahedrashare corners to form chequerboard-like sheets parallel to {001}. Atoms of Bi3+, located above and below the open squares in the sheets, form bonds to the O atoms in the sheets, thereby linking adjacent sheets into a framework. The Bi3+ atom is in lopsided 8 coordination,typical of a cation with stereoactive lone electron pairs. Kyawthuite is isostructural with synthetic β-Sb2O4 and clinocervantite (natural β-Sb2O4).

Keywords

kyawthuitenew mineralgemstoneantimonatecrystal structureMogokBurma (Myanmar)
Type
Research Article
Information
Mineralogical Magazine , Volume 81 , Issue 3 , June 2017 , pp. 477 - 484
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2017

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Enjalbert, E., Sorokina, S., Castro, A. and Galy, J. (1995) Comparison of bismuth stereochemistry in [BiO2]n and [Bi2O2]n layers. Refinement of BiSbO4 . Acta Chemica Scandinavica, 49, 813–819.CrossRefGoogle Scholar
Gunter, M.E., Bandli, B.R., Bloss, F.D., Evans, S.H., Su, S.C. and Weaver, R. (2004) Results from a McCrone spindle stage short course, a new version of EXCALIBR, and how to build a spindle stage. The Microscope, 52, 23–39.Google Scholar
Higashi, T. (2001) ABSCOR. Rigaku Corporation, Tokyo.Google Scholar
Ito, S., Kodaira, K., Tsunashima, A. and Matsushita, T. (1975) Vapor growth of bismuth antimonite single crystals. Vogyo Kyokaishi, 83, 407–410 [in Japanese].CrossRefGoogle Scholar
Kennedy, B.J. (1994) X-Ray powder diffraction study of BiSbO4 . Powder Diffraction, 9, 164–167.CrossRefGoogle Scholar
Krivovichev, S.V. (2012) Derivation of bond-valence parameters for some cation-oxygen pairs on the basis of empirical relationships between ro an. b. Zeitschrift für Kristallographie, 227, 575–579.CrossRefGoogle Scholar
Loubbidi, L., Chagraoui, A., Yakine, I., Orayech, B., Naji, M., Igartua, J.M. andTairi, A. (2014) Crystal structural and Raman vibrational studies of Bij_xSbj_xTe2x04 solid solution with 0 < x < 0.1. Open Access Library Journal, 1:170–180. https://doi.org/10.4236/oalib.1101180.Google Scholar
Mandarino, J.A. (2007) The Gladstone—Dale compatibility of minerals and its use in selecting mineral species for further study. The Canadian Mineralogist, 45, 1307–1324.CrossRefGoogle Scholar
Mills, S.J., Christy, A.G., Chen, E.C.-C. and Raudsepp, M. (2009) Revised values of the bond valence parameters for [6]Sb(V)-O and [3“n]Sb(III)-O. Zeitschrift für Kristallographie, 224, 423–431.CrossRefGoogle Scholar
Popolitov, V.I. (1996) Growth and physical properties of bismuth orthoantimonate single crystals. Zhurnal Tekhnicheskoi Fizki, 66, 203–295 [in Russian].Google Scholar
Rossman, G.R. (2006) Analytical methods for measuring water in nominally anhydrous minerals. Pp. 1–28 in. Water in Nominally Anhydrous Minerals (H. Keppler and J.R. Smyth, editors). Reviews in Mineralogy & Geochemistry, 62. Mineralogical Society and America and the Geochemical Society, Chantilly, Virginia, USA.Google Scholar
Sheldrick, G.M. (2008) A short history of SHELX. Acta Crystallographica, A64, 112–122.CrossRefGoogle Scholar
Wang, S-F., Chen, J-H., Hsu, Y-F. and Wang, Y-T. (2013) Effects of CaTiO3 addition on the densification and microwave dielectric properties of BiSbO4 ceramics. Ceramics International, 39, 2857–2861.CrossRefGoogle Scholar
You, Q., Fu, Y., Ding, Z., Wu, L., Wang, X. and Li, Z. (2011) A facile hydrothermal method to BiSbO4 nanoplates with superior photocatalytic performance for benzene and 4-chlorophenol degradations. Dalton Transactions, 40, 5774–5780.CrossRefGoogle ScholarPubMed