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Formula: KNaFe3+2(Se4+O3)2(V5+2O7).7H2O
Hydrated vanadate, selenium-bearing mineral
Crystal system: Hexagonal
Specific gravity: 2.79 measured, 2.780 calculated
Hardness: 2
Streak: Pale yellow
Colour: Yellow
Luminescence: No fluorescence under long wave or short wave UV
Solubility: Insoluble in water and slowly soluble in dilute hydrochloric acid at room temperature
Environments
Sedimentary environments
Hydrothermal environments
Yellowcatite is a new mineral, approved in 2024 and pending publication (as of May 2025).
Localities
At the type locality, School Section 32; 22-22, Thompsons Mining District, Grand County, Utah, USA,
yellowcatite was found as a post-mining mineral. It is named for the Yellow Cat Mesa and for the Yellow Cat
Road located above the underground workings of the mine
(AM 110.5.828).
The crystals are thin hexagonal plates, up to about 0.2 mm across. Yellowcatite is a
secondary, post-mining phase occurring on
montroseite - corvusite -
asphaltite - mica -bearing
sandstone. Associated minerals include
barnesite, gypsum and
mandarinoite
(Mindat).
Yellowcatite from School Section 32 -
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