Cerchiaraite

Formula: Ba₄Mn₄Si₆(O,OH,Cl)₂₆

 

Origin of name: After type locality Cerchiara manganese (braunite) mine, Val di Vara, eastern Liguria, Italy.

Crystal system: Tetragonal

Crystal class: 4/m 2/m 2/m

Twinning: 

Unit cell: a = 14.215, c = 6.126

Colour: Deep green

Diaphaneity: Transparent

Luster: Vitreous

Habit: Granular, raidial, prismatic

Hardness: 4-5

Specific gravity: 

Cleavage: None

Tenacity: Brittle, uneven

Streak: Pale green

Synonyms/varieties:

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