Formula: Cu₃As

Species:

Colour: Tin white – steel grey

Lustre: Metallic

Hardness: 3 – 3½

Specific Gravity: 7.2 – 7.9

Crystal System: Isometric

Name: Named by Wilhelm Haidinger in 1845 in honor of the Polish mineralogist Ignacy “Ignacio” Domeyko (1802–1889) who fled to Chile in the 1830s from France, after the invasion of his native country. Domeyko was professor of mineralogy at the Mining School at La Sarena, Coquimbo, Chile in 1838 and was professor at University of Chile in 1847. From 1867 to 1883, Domeyko was the head (rector) of the University of Chile.

Type Locality: Los Algodones Mine, Los Algodones district, El Arrayan, Vicuña, Elqui Province, Coquimbo – Chile

Dimorph of: Trigodomeykite

Isotypic with dienerite.