Formula: Co3(AsO4)2 . 8H2O
Origin of name: From Greek for red
Crystal system: Monoclinic
Crystal class: 2/m
Twinning:
Unit cell: a = 10.12 Ǻ, b = 13.43 Ǻ, c = 4.76 Ǻ, β = 101.9°
Colour: Colourless, pale pink to deep purplish red
Diaphaneity:
Luster: Adamantine (weakly), pearly
Habit: Crystals prismatic to acicular, often striated; bladed aggregates or stellate groups; globular tufts; fibrous, earthy
Hardness: 1.5 to 2.5
Specific gravity: 3.18
Cleavage: 3; {010} perfect, {100} and {-102} indistinct
Tenacity: Thin laminae flexible; sectile
Streak: Colourless to pink
Synonyms/varieties:
Comments: Series with annabergite and with hörnesite; streak is lighter than colour
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