Domeykite - Encyclopedia
Class : Sulfides and sulfosalts
Subclass : Arsenides
Crystal system : Cubic
Chemistry : Cu3As
Rarity : Rare
Domeykite is a rare mineral from copper and silver deposits. like algodonite, its most common companion, it concentrates arsenic from hydrothermal copper veins and "red-beds" type deposits, in which it rubs shoulders with cuprite, native copper, native silver and commonly cobalt minerals. It was named in honor of the Chilean mineralogist Ignacio Domeyko, founder of the Coquimbo School of Chemistry and Mineralogy. Domeykite is generally massive, can form masses of several kilos and sometimes acquires a botryoidal or kidney-shaped appearance ; it is extremely rare in crystals. It has a strong metallic luster and a silvery-white to steel-gray color that quickly tarnishes in air, evolving into iridescent black-brown masses that stain the fingers. It is a very accessory ore of copper and exceptionally a fine stone.
Main photo : Domeykite in 864g nodule from Mohawk Mine, Michigan, USA © Rob Lavinsky
Domeykite in the World
Twinning
No twin known for this mineral species.
Fakes and treatments
No fake listed for this mineral species.
Hardness : 3 to 3.5
Density : 7.2 to 7.9
Fracture : Irregular
Streak : Black
TP : Opaque
RI : -
Birefringence : -
Optical character : -
Pleochroism : None
Fluorescence : None
Solubility : Nitric acid
Magnetism : None
Radioactivity : None