Bostwickite

Formula:  CaMn₆Si₃O₁₆ ^. 7H₂O

Origin of name:  For Richard C. Bostwick, American mineral collector (Franklin minerals) and expert in mineral fluorescence

Crystal system:  Unknown

Crystal class:  Unknown

Twinning:

Unit cell:

Colour:  Dark red

Diaphaneity: Semitransparent

Luster:  Vitreous to submetallic

Habit:  Crystals bladed prismatic in divergent sprays or hemispheres

Hardness:  1

Specific gravity:  2.93

Cleavage:  None

Tenacity:

Streak:  Brownish red

Synonyms/varieties:

Comments: Found in a metamorphosed stratiform zinc deposit, on surfaces of ore and secondary carbonate minerals