Hubeite

Formula: Ca₂MnFeSi₄O₁₂OH·2H₂O

Origin of name: Named after the locality, Dayan mine near Huangshi, Hubei Province, China

Crystal system: Triclinic

Crystal class: 1

Twinning: 

Unit cell: a = 9.96, b = 13.875, c = 6.562, α = 133.19°, β = 101.5°, γ = 66.27°

Colour: Dark to light brown

Diaphaneity: Transparent

Luster: Vitreous

Habit: Radial, rosettes, aggregates

Hardness: 5.5

Specific gravity: 3.02

Cleavage: [001] good

Tenacity: Brittle, conchoidal fracture

Streak: Pale orange brown

Synonyms/varieties:

Comments:  Formed under mildly oxidizing conditions in a calc-manganese silicate skarn. 4-membered silicate rings structure.