Grossmanite
A very rare pyroxene with trivalent titanium — a quirk shared only with tistarite — found in meteorite inclusions.
Intro adapted from Wikipedia (CC BY-SA).
Grossmanite is an IMA-recognized mineral species in the silicate class, with the chemical formula Ca(Ti³⁺,Mg,Ti⁴⁺)AlSiO₆.
It crystallizes in the monoclinic crystal system (space group C2/c). It is a member of the Pyroxene structural group.
Key properties: specific gravity 3.41.
IMA symbol Gsm, IMA status: approved, named in 2008.
Likely formed through high-temperature condensation in the solar nebula, followed by melting and crystallization in Ca-, Al-rich refractory inclusions in a meteorite.
It is found associated with Spinel, perovskite, grossite, melilite.
The mineral was named to honor Lawrence Grossman (b. 1946), Professor of Cosmochemistry, University of Chicago, USA, for his fundamental contributions to meteorite research.