Athabasca Saskatchewan, Canada — Photo: Pacific Museum of Earth from Canada · CC BY-SA 2.0
Uraninite
Also known as: Pitchblende, Uranium ore.
Uranium dioxide — 'pitchblende' — the heavy, black, radioactive primary ore of uranium.
Intro adapted from Wikipedia (CC BY-SA).
Uraninite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula UO₂.
It crystallizes in the cubic crystal system (space group Fm3m). It is a member of the Fluorite structural group.
Key properties: Mohs hardness 5–6; specific gravity 10.63–10.95; typically black or gray or brown; Brownish black, gray, olive-green, shining streak; Submetallic to greasy, dull luster.
IMA symbol Urn, grandfathered status — known before the IMA’s founding, named in 1845.
Found in granite and syenite pegmatites; in hydrothermal high-temperature tin and moderate-temperature Co–Ni–Bi–Ag–As and other sulfide veins; in Colorado Plateau-type sandstone-hosted U–V deposits; in uraniferous conglomerates.
It is found associated with Zircon, monazite, tourmaline, mica, feldspar (pegmatitic); pyrite, chalcopyrite, galena, bismuth, silver, nickeline, barite, fluorite.
The name refers to URANium in the composition.
Collections: Rare & Remarkable, Metals & Native Elements.