Gageite

Formula:  (Mn,Mg,Zn)₄₂Si₁₆O₅₄(OH)₄₀

Origin of name:  For Robert Gage, American chemist

Crystal system:  Triclinic

Crystal class:  -1

Twinning:

Unit cell: a = 19.42 Ǻ, b = 19.42 Ǻ, c = 9.84 Ǻ, α = 76.5°   β = 76.6°   γ = 86.9°

Colour:  Colourless to pink

Diaphaneity:

Luster:  Vitreous

Habit:  Crystals acicular, microscopic; radial aggregates, bundles or matted fibres

Hardness:  3

Specific gravity:  3.46

Cleavage:  1; {110} distinct

Tenacity:

Streak:

Synonyms/varieties:

Comments:  Data are for gageite-2M; there is also a -1A polytype