Formula: Cu₂(OH)₃Cl

Species: Halides

Colour: Green to dark greenish-black, greenish-blue.

Lustre: Adamantine, Vitreous

Hardness: 3

Specific Gravity: 3.77 (Calculated)

Crystal System: Monoclinic

Member of: Atacamite Group

Name: Named in allusion to its monoclinic morphology and relationship to Atacamite.

Type Locality: Chuquicamata Mine, Chuquicamata District, Calama, El Loa Province, Antofagasta – Chile

Polymorph of: Atacamite, Botallackite. Easily confused with the closely related paratacamite.