Martyite

martyite

rossite

montroseite

magnesiopascoite

Images

Formula: Zn3V2O7(OH)2.2H2O
Hydrated normal vanadate, volborthite group
Crystal System: Trigonal
Specific gravity: 3.37 measured, 3.375 calculated
Hardness: 3
Streak: Pale yellow-orange
Colour: Pale orange-yellow
Solubility: Dissolves rapidly in cold hydrochloric acid
Environments

Sedimentary environments
Hydrothermal environments

Localities

At the type locality, the Blue Cap mine, La Sal Creek Mining District, San Juan County, Utah, USA, martyite occurs in association with gypsum, rossite, pyrite, montroseite and magnesiopascoite on a vanadium-uranium oxide-replacement assemblage developed at the expense of organic material. All samples of martyite were recovered from a single isolated pillar in the mine. Other minerals identified from the mine are brochantite, calcite, coffinite, devilline, dickthomssenite, dolomite, lasalite, navajoite, sherwoodite, uraninite, uranopilite and zeunerite.
Uranium–vanadium mineralisation in the mines of the area occurs in certain layers of the sandstone. Carbonaceous material in these layers is considered to have created a reducing environment, which caused the precipitation of uranium and vanadium oxides, such as uraninite, corvusite and montroseite, from solution. Martyite, magnesiopascoite and rossite appear to have formed from post-mining leaching and oxidation of vanadium oxides by circulating groundwater (CM 46.687-692).

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