Light pink grains of chegemite associated with light yellow katoite-wadalite and white larnite. Field of view 1.5 cm. From: Lakargi Mountain, Upper Chegem volcanic caldera, Baksan Valley, Kabardino-Balkaria, Russia. — Photo: Leon Hupperichs · CC BY-SA 3.0
Chegemite
Chegemite is an IMA-recognized mineral species in the silicate class, with the chemical formula Ca₇(SiO₄)₃(OH)₂.
It crystallizes in the orthorhombic crystal system (space group Pbnm). It is a member of the Humite structural group.
Key properties: Mohs hardness 5.5–6; specific gravity 2.86; White streak; Vitreous luster.
IMA symbol Cgm, IMA status: approved, named in 2008.
A product of sanidinite facies metamorphism of calcareous xenoliths in ignimbrite.
It is found associated with Larnite, spurrite, rondorfite, reinhardbraunsite, wadalite, lakargiite, srebrodolskite.
The name refers to the Chegem River, in the headwater area of which the new mineral was discovered.