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Sulfosalt

Ustarasite

Pb(Bi,Sb)₆S₁₀
Hardness2.5
ClassSulfosalt
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Ustarasite specimen

Silver-grey microcrystals of the extremely rare mineral ustarasite from the type locality in Ustarasai deposit, Uzbekistan. Ustarasite is a Pb-Bi sulphosalt. Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0

Ustarasite

Ustarasite is an IMA-recognized mineral species in the sulfosalt class, with the chemical formula Pb(Bi,Sb)₆S₁₀.

Key properties: Mohs hardness 2.5; Metallic. Anisotropism: Strong. R1 –R2: n.d luster.

IMA symbol Utr, IMA status: questionable, named in 1955.

Found in quartz-bismuthinite veins (Ustarasai deposit, Uzbekistan).

It is found associated with Bismuthinite, kobellite, bismuthian jamesonite, quartz (Ustarasai deposit, Uzbekistan).

The name is derived from the locality of first discovery, the Ustarasai deposit, Uzbekistan.

Index entry. This entry combines official IMA/RRUFF species data with published physical-property data — a full written entry hasn’t been published yet. Browse more U minerals or help write this entry.