HUGHESITE, Na3al(V10O28)•22H2O, a NEW MEMBER of the PASCOITE FAMILY of MINERALS from the SUNDAY MINE, SAN MIGUEL COUNTY, COLORADO
1253 The Canadian Mineralogist Vol. 49, pp. 1253-1265 (2011) DOI : 10.3749/canmin.49.5.1253 HUGHESITE, Na3Al(V10O28)•22H2O, A NEW MEMBER OF THE PASCOITE FAMILY OF MINERALS FROM THE SUNDAY MINE, SAN MIGUEL COUNTY, COLORADO JOHN RAKOVAN§AND GREGORY R. SCHMIDT Department of Geology, Miami University, Oxford, Ohio 45056, U.S.A. MICKEY E. GUNTER Department of Geological Sciences, University of Idaho, Moscow, Idaho 83844, U.S.A. BARBARA NASH Department of Geology, University of Utah, Salt Lake City, Utah 84112, U.S.A. JOE MARTY 3457 E. Silver Oak Road, Salt Lake City, Utah 84108, U.S.A. ANTHONY R. KAMPF Mineral Sciences Department, Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, California 90007, U.S.A. WILLIAM S. WISE Department of Earth Science, University of California, Santa Barbara, California 93106, U.S.A. ABSTRACT We report on the discovery, description and solution of the structure of a new member of the pascoite family of minerals, hughesite, from the Sunday mine, Gypsum Valley, San Miguel County, Slick Rock District, Colorado, USA (38°4’19” N, 108°48’15” W). Orange to golden orange crystals of hughesite occur in efflorescent crusts, averaging 2 mm thick, on the sandstone walls of mine workings and in rock fractures. Hughesite forms through the oxidation of corvusite, (Na,Ca,K)1–x 5+ 4+ 2+ 3+ 2+ 4+ (V ,V ,Fe )8O28•4H2O, and montrosite, (V ,Fe ,V )O(OH), the primary vanadium oxide phases present, as they react with acidic, oxidizing groundwater. Crystals vary in habit, including blocky, spear-shaped, and platy, with one good cleavage on (001).
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