Anhydrous normal arsenate, monazite group, paramorph of tetrarooseveltite
Specific gravity: 6.86 to 7.01
Hardness: 4 to 4½
Colour: White to pale grey, pale green, yellow
Solubility: Soluble in acids
Volcanic igneous environments
Rooseveltite is a very rare arsenate that occurs in cassiterite veinlets in
rhyolite-dacite lava flows
in thin botryoidal crusts and fine-grained aggregates pseudomorphic after
At the San Francisco de los Andes mine, Calingasta, Calingasta Department, San Juan Province, Argentina, rooseveltite has been found in the oxidised zone of a breccia pipe (HOM).
At the type locality, Santiaguillo, Macha area, Chayanta Province, Potosí, Bolivia, rooseveltite is a very rare mineral found as a crystalline crust on cassiterite veinlets in rhyolite-dacite lava flows, associated with cassiterite (AM 32.372 ).
At the Moldava deposit, Teplice District, Ústí nad Labem Region, Czech Republic, rooseveltite has been found associated with preisingerite, bismutite, mixite, zavaritskite and wulfenite (HOM).
In Uzbekistan, rooseveltite has been found associated with conichalcite and mixite (HOM).
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