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Formula: Bi(AsO4)
Anhydrous normal arsenate, monazite group,
paramorph of
tetrarooseveltite
Crystal System: Monoclinic
Specific gravity: 6.86 to 7.01 measured, 7.21 calculated
Hardness: 4 to 4½
Streak: White
Colour: White to pale grey, pale green, yellow
Solubility: Soluble in acids
Environments
Volcanic igneous environments
Hydrothermal environments
Rooseveltite is a very rare arsenate that occurs in cassiterite veinlets in
rhyolite-dacite lava flows
(Webmin), and
in thin botryoidal crusts and fine-grained aggregates pseudomorphic after
bismuthinite
(Dana).
Localities
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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