Wollastonite
Image: <a href="//commons.wikimedia.org/wiki/User:Archaeodontosaurus" title="User:Archaeodontosaurus">Didier Descouens</a> (CC BY-SA 3.0)
Mineral NameWollastonite
Chemical FormulaCaSiO3
Mohs Hardness4.5
Crystal Systemtriclinic
Lustervitreous
Streak Colorwhite
Cleavageperfect on {100} and {001}, good on {102}
Fractureuneven
Specific Gravity2.9
Colorswhite, grey, light green, pale brown
Transparencytranslucent
Type LocalityTranomaro-Maromby area, Amboasary District, Anosy (Fort Dauphin) Region, Tuléar (Toliara) Province, Madagascar
Mineral Groupsilicates
Usesindustrial filler, ceramic raw material, flux in metallurgy, collector
Associated Mineralsgarnet, diopside, vesuvianite, calcite, quartz
Raritycommon
Description
This specimen displays a blocky aggregate of bladed to fibrous wollastonite crystals, predominantly off-white to light grey-green, with some areas showing brownish staining and a pearly luster.
Geological Context
Wollastonite commonly forms in contact metamorphic environments, especially in metamorphosed impure limestones or dolomites (skarns) where silica-rich fluids react with calcium carbonate.
