Taramellite

cyclsilicate

boron

Formula: Ba4(Fe3+,Ti)4O2[B2Si8O27]Clx
Cyclosilicate (ring silicate), taramellite group
Specific gravity: 3.92
Hardness: 5½
Streak: Brown
Colour: Bronze-purple, reddish brown, brownish violet
Solubility: Insoluble in acids
Environments:

Metamorphic environments

Taramellite is a contact-metamorphic mineral associated with calcite, magnetite, chalcopyrite, pyrite, pyroxene, actinolite and celsian.
At the type locality, Candoglia marble quarries, Piedmont, Italy, taramellite occurs in metamorphic rocks rich in barium silicates, in contact with granitic rocks and associated with pyrite, magnetite, diopside, chalcopyrite, celsian, calcite and actinolite.
At Langban, Sweden, taramellite occurs in a metamorphosed Fe-Mn ore body associated with quartz, calcite, hematite, barylite, baryte, manganoan pectolite, K-feldspar, manganoan garnet, melanotekite, barian hedyphane, rhodonite and manganoan aegirine.

Common impurities: Mn,Pb,Ca,Na,K,H2O

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