Formula: (Mn,Mg)3Zn2(AsO4)(OH,O)6
Origin of name: From Greek for green and purple-red
Crystal system: Monoclinic
Crystal class: 2/m
Twinning:
Unit cell: a = 22.97 Ǻ, b = 3.29 Ǻ, c = 7.31 Ǻ, β = 106.2°
Colour: Light gray-green in daylight, purple-red in artificial light
Diaphaneity:
Luster: Vitreous to pearly
Habit: Crystals slender prismatic, elongated and striated; needles, matted fibres
Hardness: 3 to 3.5
Specific gravity: 3.46
Cleavage: 1; {100} distinct
Tenacity: Brittle
Streak:
Synonyms/varieties:
Comments:
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