Anthonyite

Formula:  Cu(OH,Cl)₂^.3H₂O

Origin of name:  For John Williams Anthony (1920-1992), American mineralogist, University of Arizona, Tucson, Arizona, USA

Crystal system:  Monoclinic

Crystal class:  2/m

Twinning:

Unit cell:

Colour:  Lavender, violet

Diaphaneity: Semi-transparent

Luster:

Habit:  Crystals prismatic, often curved, as crusts

Hardness:  2

Specific gravity:

Cleavage:  1; {100} good

Tenacity: Sectile, crystals bending easily on the {100}cleavage

Streak:

Synonyms/varieties:

Comments: Observed in cavities and fractures in basalt, formed by the action of chlorine-bearing connate waters on copper.