wollastonite
Sign in to saveWollastonite is a calcium inosilicate mineral (CaSiO3) that may contain small amounts of iron, magnesium, and manganese substituting for calcium. It is usually white. It forms when impure limestone or dolomite is subjected to high temperature and pressure, which sometimes occurs in the presence of silica-bearing fluids as in skarns or in contact with metamorphic rocks. Associated minerals include garnets, vesuvianite, diopside, tremolite, epidote, plagioclase feldspar, pyroxene and calcite. It is named after the English chemist and mineralogist William Hyde Wollaston (1766–1828).
Key facts
- Mineral.name
- Wollastonite
- Mineral.category
- Inosilicate mineral
- Mineral.image
- WollastoniteUSGOV.jpg
- Mineral.formula
- Calcium metasilicate, CaSiO3
- Mineral.IMAsymbol
- Wo
- Mineral.molweight
- 116.159g/mol
- Mineral.strunz
- 9.DG.05
- Mineral.system
- Triclinic Monoclinic polytype exists
- Mineral.class
- Pinacoidal () (same H-M symbol)
- Mineral.symmetry
- P (Triclinic) P21/a (Monoclinic)
- Mineral.unit cell
- a = 7.925 Å, b = 7.32 Å, c = 7.065 Å; α = 90.055°, β = 95.217°, γ = 103.42°; Z = 6
- Mineral.color
- White, colorless or gray
- Mineral.habit
- Rare as tabular crystals—commonly massive in lamellar, radiating, compact and fibrous aggregates.
- Mineral.twinning
- Common
- Mineral.cleavage
- Perfect in two directions at near 90°
- Mineral.fracture
- Splintery to uneven
- Mineral.mohs
- 4.5 to 5.0
- Mineral.luster
- Vitreous or dull to pearly on cleavage surfaces
via Wikipedia infobox
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Encyclopedic overview
14 sectionsContents
- Production trends
- Uses
- Ceramics
- Construction
- Metallurgy
- Paint
- Plastic
- Substitutes
- Composition
- Geologic occurrence
- Structure
- See also
- References
- External links
Wollastonite is a calcium inosilicate mineral (CaSiO3) that may contain small amounts of iron, magnesium, and manganese substituting for calcium. It is usually white. It forms when impure limestone or dolomite is subjected to high temperature and pressure, which sometimes occurs in the presence of silica-bearing fluids as in skarns or in contact with metamorphic rocks. Associated minerals include garnets, vesuvianite, diopside, tremolite, epidote, plagioclase feldspar, pyroxene and calcite. It is named after the English chemist and mineralogist William Hyde Wollaston (1766–1828).
Despite its chemical similarity to the compositional spectrum of the pyroxene group of minerals—where magnesium (Mg) and iron (Fe) substitution for calcium ends with diopside and hedenbergite respectively—it is structurally very different, with a third tetrahedron in the linked chain (as opposed to two in the pyroxenes).
Excerpted from Wikipedia’s “wollastonite” article, available under the CC BY-SA 4.0 licence.