Esseneite - France, Aveyron, Rodez, Lapanouse-de-Sévérac Slags - crystal 0,5 mm high — Photo: Henk Smeets · CC BY 4.0
Esseneite
The ferric-iron-dominant pyroxene of the CaFeAlSiO₆ formula — the iron analogue of davisite, grossmanite and kushiroite.
Intro adapted from Wikipedia (CC BY-SA).
Esseneite is an IMA-recognized mineral species in the silicate class, with the chemical formula CaFe³⁺AlSiO₆.
It crystallizes in the monoclinic crystal system (space group C2/c). It is a member of the Pyroxene structural group.
Key properties: Mohs hardness 6; specific gravity 3.54; White streak; Vitreous luster; optically biaxial.
IMA symbol Ess, IMA status: approved, named in 1985.
A high-temperature, low-pressure, oxidized and quenched crystallization product derived from fused sediments contiguous to naturally combusted coal seams.
It is found associated with Anorthite, melilite, magnetite-hercynite, glass.
The name refers to Dr. Eric J. Essene, Professor at the University of Michigan, Ann Arbor, Michigan, USA, and discoverer of the first specimens.