Unit cell of synthetic torbernite (Cu[(UO2)(PO4)]2(H2O)12) (U = dark green, Cu = light green, O = red, P = yellow, O(H2O) = grey, H = lightgrey) — Photo: Klaproth · CC BY-SA 4.0
Torbernite
Also known as: Copper uranium mica.
A hydrated copper uranyl phosphate — brilliant emerald-green radioactive plates, the 'uranium mica'.
Intro adapted from Wikipedia (CC BY-SA).
Torbernite is an IMA-recognized mineral species in the phosphate class, with the chemical formula Cu(UO₂)₂(PO₄)₂·12H₂O.
It crystallizes in the tetragonal crystal system (space group P4/nnc).
Key properties: Mohs hardness 2–2.5; specific gravity 3.22; typically green; Pale green streak; Vitreous, subadamantine, waxy, pearly on cleavages; becoming dull on dehydration to metatorbernite luster; refractive index 1.586; optically uniaxial.
IMA symbol Tor, IMA status: approved, named in 1790.
An uncommon secondary mineral formed in the oxidized zone of some uraniferous copper deposits.
It is found associated with Metatorbernite, autunite, zeunerite, uraninite.
The mineral was named to honor Torbern Olof Bergmann (1735-1784), Swedish chemist and mineralogist, Professor of Chemistry, Uppsala University, Uppsala, Sweden.
Collections: Collector Favorites, Rare & Remarkable.