Antlerite

Formula:  Cu₃(SO₄)(OH)₄

Origin of name:  From locality; Antler mine, Mohave Co. Arizona

Crystal system:  Orthorhombic

Crystal class:  2/m 2/m 2/m

Twinning:

Unit cell:   a = 8.25 Å, b = 12.01 Å, c = 6.04 Å

Colour:  Emerald-green to blackish green, light green

Diaphaneity: Translucent

Luster:  Vitreous

Habit:  Crystals thick tabular, short prismatic, equant; aggregates of fibrous or acicular crystals; cross-fibre veinlets, granular

Hardness:  3.5

Specific gravity:  3.88

Cleavage:  2; {010} perfect, {100} indistinct

Tenacity:  Brittle

Streak:  Pale green

Synonyms/varieties:  Arnimite, stelznerite

Comments: Found in secondary, weathered zone of carbonate-poor copper deposits