Extremely rare cadmium selenium mineral cadmoselite from the type locality: Ust' Uyok Deposit, Turan District, Tuva Republic, Russian Federation. Specimen analyzed by SEM/EDS. Ex Vandenbroucke Museum collection specimen, from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Cadmoselite
A rare hexagonal cadmium selenide occurring as black to pale-grey grains.
Intro adapted from Wikipedia (CC BY-SA).
Cadmoselite is an IMA-recognized mineral species in the sulfide class, with the chemical formula CdSe.
It crystallizes in the hexagonal crystal system (space group P6_3mc). It is a member of the Wurtzite structural group.
Key properties: Mohs hardness 4; specific gravity 5.47; Black streak; Resinous to adamantine. Anisotropism: Weak. R1 –R2: n.d luster.
IMA symbol Cds, grandfathered status — known before the IMA’s founding, named in 1957.
Found in sedimentary strata, under reducing secondary conditions of medium to high alkalinity (Ust’Uyuk deposit, Russia).
It is found associated with Ferroselite, clausthalite, cadmian sphalerite, selenium, greenockite, pyrite, laumontite, calcite (Ust’Uyuk deposit, Russia).
The name refers to the presence of cadmium and selenium.