|Also called: titanite a brown, yellow, green, or grey lustrous mineral consisting of calcium titanium silicate in monoclinic crystalline form. It occurs in metamorphic and acid igneous rocks and is used as a gemstone. Formula: CaTiSiO5|
|[C19: from French sphène, from Greek sphēn a wedge, alluding to its crystals]|
titanium and calcium silicate mineral, CaTiSiO4(O,OH,F), that, in a crystallized or compact form, makes up a minor component of many igneous rocks and gneiss, schist, crystalline limestone, and pegmatite. Occurrences include the Tirol, Austria; Trentino, Italy; Norway; Switzerland; Madagascar; and the United States (New York). Titanite's relatively high dispersion causes it to be a brilliant gem of various colours; it is usually faceted. For detailed physical properties, see silicate mineral (table)
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