Beta-roselite

Formula:  Ca₂Co(AsO₄)₂ ^. 2H₂O

Origin of name:  For Gustav Rose, German mineralogist

Crystal system:  Triclinic

Crystal class:  Unknown

Twinning:

Unit cell: a = 5.88 Ǻ, b = 7.67 Ǻ, c = 5.58 Ǻ, α = 112.3°, β = 71.4°, γ = 119.7°

Colour:  Dark rose-red

Diaphaneity:

Luster:  Vitreous

Habit:  Crystals not common; granular masses

Hardness:  3.5 to 4

Specific gravity:  3.71

Cleavage:  1; {010} perfect

Tenacity:

Streak:

Synonyms/varieties:

Comments:  Dimorphous with roselite