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Margaritasite: a new mineral of hydrothermal origin from the Pena Blanca uranium district, Mexico.

American Mineralogist

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Abstract

Margaritasite, (Cs,K,H3O)2(UO2)2V2O8.nH2O (where Cs > K, H3O and n approx 1), a 10.514, b 8.425, c 7.25 A, beta 106.01o, P21/a, Z = 2, is a newly recognized uranium ore mineral named for the Margaritas deposit, Pena Blanca uranium district, Chihuahua, Mexico, at which it was discovered. A Cs-rich analogue of carnotite, margaritasite is the natural equivalent of synthetic Cs-uranyl vanadate (A.M. 43- 799, 50-825). A fine-grained yellow mineral, it is most easily distinguished from carnotite by XRD; X-ray powder patterns (CuKalpha radiation) show that the (001) reflection of margaritasite lies at 12.7o (2theta ), while that of carnotite is found at 13.8o (2theta ). The shift of the (001) reflection in margaritasite reflects the structural changes caused when Cs occupies the sites filled by K in carnotite. Synthesis experiments indicate that margaritasite also differs from carnotite in a higher-T hydrothermal origin. Chemical analyses and XRD data for margaritasite and synthetic Cs- carnotite, and chemical analyses for rocks from Sierra Pena Blanca and vicinity, are tabulated.-J.A.Z.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Margaritasite: a new mineral of hydrothermal origin from the Pena Blanca uranium district, Mexico.
Series title:
American Mineralogist
Volume
67
Issue:
11-12
Year Published:
1982
Language:
English
Publisher:
Mineralogical Society of America
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
American Mineralogist
First page:
1273
Last page:
1289
Number of Pages:
17