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Lead-tellurium oxysalts from Otto Mountain near Baker, California: III. Thorneite, Pb_6(Te_2^(6+)O_(10))(CO_3)Cl_2(H_2O), the first mineral with edge-sharing octahedral tellurate dimers

Kampf, Anthony R. and Housley, Robert M. and Marty, Joseph (2010) Lead-tellurium oxysalts from Otto Mountain near Baker, California: III. Thorneite, Pb_6(Te_2^(6+)O_(10))(CO_3)Cl_2(H_2O), the first mineral with edge-sharing octahedral tellurate dimers. American Mineralogist, 95 (10). pp. 1548-1553. ISSN 0003-004X. https://resolver.caltech.edu/CaltechAUTHORS:20101028-090032988

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Abstract

Thorneite, Pb_6(Te_2^(6+)O_(10))(CO_3)Cl_2(H_2O), is a new tellurate from Otto Mountain near Baker, California, named in honor of Brent Thorne. The new mineral occurs on fracture surfaces and in small vugs in brecciated quartz veins. Thorneite is directly associated with acanthite, cerussite, gold, hessite, iodargyrite, khinite, wulfenite, and three other new tellurates: housleyite, markcooperite, and ottoite. Various other secondary minerals occur in the veins, including three other new secondary tellurium minerals: paratimroseite, telluroperite, and timroseite. Thorneite is monoclinic, space group C2/c, a = 21.305(1), b = 11.059(1), c = 7.564(1) Å, β = 101.112(4)°, V = 1748.8(4) Å^3, and Z = 4. Crystals are prismatic to bladed with elongation and striations parallel to c and typically occur in parallel and random aggregates. It is yellow and transparent, with pale yellow streak and adamantine luster. Mohs hardness is estimated at 2. The mineral is brittle, with an irregular to splintery fracture and good {100} cleavage. The calculated density is 6.828 g/cm^3. Thorneite is biaxial (+), with large 2V, but indices of refraction are too high to be measured. The optic orientation is Y = b, Z ^ a = 29° in obtuse β. No pleochroism was observed. Electron microprobe analysis provided PbO 73.90, ZnO 0.03, TeO_3 20.35, Cl 2.29, H_2O 1.28 (structure), CO_2 2.29 (structure), O≡Cl –0.52, total 99.62 wt%; the empirical formula (based on O+Cl = 16) is (Pb_(5.94)Zn_(0.01))(Te_(2.08)^(6+)O_(10))(C_(1.00)O_3)[Cl_(1.16)O_(0.34)(OH)_(0.50)](H_2O). The strongest powder X-ray diffraction lines are [d_(obs) in Å (hkl) I]: 10.43 (200) 35, 3.733 (5[overbar]11, 2[overbar]02, 002) 27, 3.595 (4[overbar]21) 33, 3.351 (112) 66, 3.224 (511, 131) 100, 3.093 (2[overbar]22, 3[overbar]31) 30, 2.900 (6[overbar]21) 44, 2.133 (821, 622, 223, 731, 242) 38. The crystal structure (R_1 = 0.028) contains edge-sharing octahedral tellurate dimers, [Te_2^(6+)O_(10)]^(8–) that bond to Pb atoms, which in turn are linked via bonds to Cl atoms, CO_3 triangles, and H_2O molecules.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.2138/am.2010.3512 DOIUNSPECIFIED
http://ammin.geoscienceworld.org/cgi/content/abstract/95/10/1548PublisherUNSPECIFIED
Additional Information:© 2010 Mineralogical Society of America. Manuscript received January 28, 2010. Manuscript accepted May 5, 2010. Manuscript handled by G. Diego Gatta. We thank Associate Editor G. Diego Gatta, Technical Editor Ronald C. Petersen, referees Elena Sokolova and Filippo Vurro, and Stuart J. Mills for helpful comments on the manuscript. The Raman studies were conducted in the laboratory of George R. Rossman at the California Institute of Technology and with his assistance. The EMP analyses were supported by a grant to the California Institute of Technology from the Northern California Mineralogical Association. The remainder of this study was funded by the John Jago Trelawney Endowment to the Mineral Sciences Department of the Natural History Museum of Los Angeles County.
Funders:
Funding AgencyGrant Number
Northern California Mineralogical Association UNSPECIFIED
John Jago Trelawney Endowment UNSPECIFIED
Subject Keywords:Thorneite; new mineral; tellurate; crystal structure; Otto Mountain; California
Issue or Number:10
Record Number:CaltechAUTHORS:20101028-090032988
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20101028-090032988
Official Citation:Anthony R. Kampf, Robert M. Housley, and Joseph Marty Lead-tellurium oxysalts from Otto Mountain near Baker, California: III. Thorneite, Pb6(Te26+O10)(CO3)Cl2(H2O), the first mineral with edge-sharing octahedral tellurate dimers American Mineralogist, October; 95: 1548 - 1553.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:20577
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:17 Nov 2010 17:48
Last Modified:03 Oct 2019 02:12

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