Bustamite

bustamite

glaucochroite

wollastonite

johannsenite

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Formula: CaMn2+Si2O6
Inosilicate (chain silicate), wollastonite group, manganese-bearing mineral
Specific gravity: 3.32 to 3.43
Hardness: 5½ to 6½
Streak: White
Colour: Pale to medium pink; brownish red; colourless to yellowish pink in transmitted light. Pink colour fades on exposure to sunlight
Solubility: Partly soluble in hydrochloric acid
Environments:

Metamorphic environments

Bustamite occurs in manganese ores formed by metamorphism of manganese-bearing sediments. The type locality is a carbonate-silicate hosted zinc deposit. Common associates include calcite, diopside, glaucochroite, grossular, johannsenite, rhodonite and wollastonite.

Alteration

bustamite, tephroite and calcite to glaucochroite and CO2
CaMn2+Si2O6 + Mn2+2(SiO4) + 2CaCO3 ⇌ 3CaMn2+(SiO4) + 2CO2
(DHZ 1A p348)

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