Aktashite Dimensions: 2.2 cm x 2.2 cm x 0.9 cm Locality: Moctezuma, Mun. de Moctezuma, Sonora, Mexico Aktashite is a very rare, gray, Cu-Hg-As sulfosalt of hydrothermal origin found in complex polymetallic As/Hg-bearing deposits. Gray aktashite is richly dispersed on matrix along with other rare species from this very unusual and obscure Mexican locale. There is probably mint-green, fibrous emmonsite plus an unknown green mineral. Ex. American Museum Collection. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Aktashite
A rare sulfosalt of copper, mercury and arsenic — the only known sulfosalt containing essential copper and mercury together.
Intro adapted from Wikipedia (CC BY-SA).
Aktashite is an IMA-recognized mineral species in the sulfosalt class, with the chemical formula Cu₆Hg₃As₄S₁₂.
It crystallizes in the hexagonal crystal system (space group R3). It is a member of the Nowackiite structural group.
Key properties: Mohs hardness 3.5; specific gravity 5.5; Black streak; Metallic. Anisotropism: Weak, in shades of blue luster.
IMA symbol Ats, IMA status: approved, named in 1968.
Uncommon, of hydrothermal origin in complex polymetallic As-Hg-bearing deposits.
It is found associated with Stibnite, chalcostibite, mercurian tetrahedrite, tennantite, luzonite, enargite, cinnabar, chalcopyrite, pyrite, sphalerite, realgar, orpiment, dickite.
The name refers to its occurrence at the Aktash deposit, Russia.