Clinoenstatite
The monoclinic form of magnesium silicate (MgSiO₃) — the low-symmetry counterpart of the common pyroxene enstatite.
Intro adapted from Wikipedia (CC BY-SA).
Clinoenstatite is an IMA-recognized mineral species in the silicate class, with the chemical formula Mg₂Si₂O₆.
It crystallizes in the monoclinic crystal system (space group P2_1/c). It is a member of the Pyroxene structural group.
Key properties: Mohs hardness 5–6; specific gravity 3.21; optically biaxial.
IMA symbol Cen, IMA status: approved, named in 1906.
Occurs as phenocrysts, likely inverted from \protoenstatite, " in high-magnesium nonfeldspathic andesites. Exsolved in diopside in ultramafic rocks and in enstatite in high-grade metamorphic hornfelses.
It is found associated with Diopside, enstatite, chromite, \hypersthene, " glass.
The name refers to its monoclinic crystal system and chemical identity to enstatite.