Crookesite is a selenide mineral composed of copper and selenium with variable thallium and silver.
Characteristics
Its chemical formula is reported either as Cu7(Tl, Ag)Se4 or (Cu, Tl, Ag)2Se.1 It is formed by precipitation from hydrothermal fluids, and contains by mass: 16.3% Tl, 47.3% Cu, 2.9% Ag, and 33.6% Se.2
Crookesite is an opaque, bluish grey to pink toned brown metallic mineral crystallizing in the tetragonal system. It has a Mohs hardness of 2.5 to 3 and a specific gravity of 6.9.
Name and discovery
It was discovered in 1866 in Skrikerum, Sweden and named for Sir William Crookes (1832–1919), the discoverer of the element thallium.3
See also
- List of minerals
- List of minerals named after people
- Sabatierite – Selenide of copper and thallium
- Berger, Rolf A.; Sobott, Robert J. (1987). "Characterization of TlCu7S4, a crookesite analogue". Monatshefte für Chemie. 118 (8–9): 967–972. doi:10.1007/BF00815324. S2CID 102058943.
- Berger, R..A. (1987). "Crookesite and sabatierite in a new light. A crystallographer's comment" (PDF). Zeitschrift für Kristallographie. 181 (1–4): 241–249. Bibcode:1987ZK....181..241B. doi:10.1524/zkri.1987.181.1-4.241.
References
http://www.mindat.org/min-1159.html Mindat http://www.mindat.org/min-1159.html ↩
Webmineral site http://webmineral.com/data/Crookesite.shtml ↩
Webmineral site http://webmineral.com/data/Crookesite.shtml ↩