Carnotite

carnotite [′kär·nə‚tīt]

(mineralogy)

K(UO₂)₂(VO₄)₂·nH₂O A canary-yellow, fine-grained hydrous vanadate of potassium and uranium having monoclinic microcrystals; an ore of radium and uranium.

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Carnotite 

(named after the French chemist M.-A. Carnot, 1838–1920), a mineral, a complex vanadate of potassium and uranium from the group of uran-micas. Its composition is K2(U02)2[V20₈]-3H₂0. Carnotite contains admixtures of Ca (up to 3.3 percent) and insignificant amounts of Cu, Pb, and other elements. The structure is complex and lamellar, which is evident from its good mica-like cleavage. Monoclinic-system crystals are rare; granular and powdery aggregates, which are bright yellow and greenish yellow in color, are common. The mineral has a hardness of 2–3 on the mineralogical scale and a density of 4, 460 kg/m³. It is highly radioactive, containing up to 63.42 percent UO₃.

Carnotite is ordinarily found in zones of weathering of sedi-mentary rocks rich in organic remains. It was first discovered invanadium-bearing sandstones of Jurassic age in the states ofUtah and Colorado in the United States. It has also been foundin calcareous sandstones in the province of Shaba in the Republicof Zaire, at Radium Hill in Australia, and elsewhere. It is avaluable ore of uranium and vanadium.