Grossmanite is a very rare mineral of the pyroxene group,Mindat, Grossmanite, http://www.mindat.org/min-39426.html with formula CaTi3+AlSiO6.Ma, C., and Rossmann, G.R., 2009: Grossmanite, CaTi3+AlSiO6, a new pyroxene from the Allende meteorite. American Mineralogist 94(10), 1491–1494 It is the titanium-dominant member. Grossmanite is unique in being a mineral with trivalent titanium, a feature shared with tistarite, Ti2O3.Mindat, Tistarite, http://www.mindat.org/min-38695.html Titanium in minerals is almost exclusively tetravalent. Grossmanite stands for titanium-analogue of davisite, esseneite and kushiroite – other members of the pyroxene group. Both grossmanite and tistarite come from the famous Allende meteorite.
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