Gummite (redirected from Pechuran)

gummite [′gə‚mīt]

(mineralogy)

Any of various yellow, orange, red, or brown secondary minerals containing hydrous oxides of uranium, thorium, and lead. Also known as uranium ocher.

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Gummite 

mineral formations of unstable composition that comprise mixtures of cryptocrystalline aggregates consisting of hydrated oxides and some uranium hydrosilicates. The principal minerals that form gummite are clarkeite (Na, K)₂ − _2r(Ca. Pb)_rU₂O₇.y H₂O, fourmarierite PbO-4UO₃-7—8H₂0, and kasolite Pb(U0₂)[Si0₄]H₂0; they are rarely found in pure form. Gummite forms thin crusts and irregular or circular concretions with a conchoidal fracture and a light-yellow or red-orange resinous luster. Its hardness on the mineralogical scale is 2.5–3 and its density. 4,700–5,800 kg/m³. Gummite is brittle. It develops as a result of changes in uraninite or pitchblende in the zone of oxidation of primary uranium ores.

G. P. BARSANOV