Jeffbenite
Jeffbenite is an IMA-recognized mineral species in the silicate class, with the chemical formula Mg₃Al₂Si₃O₁₂.
It crystallizes in the tetragonal crystal system (space group I-42d). It is a member of the Jeffbenite structural group.
Key properties: Mohs hardness 7; specific gravity 3.576; White streak; Vitreous luster; optically uniaxial.
IMA symbol Jef, IMA status: approved, named in 2014.
Part of a composite inclusion with omphacitic pyroxene in an alluvial diamond; likely trapped in diamond in the deep upper mantle.
It is found associated with Ferropericlase, omphacitic pyroxene, CaSiO3 -walstromite, olivine, diamond.
Previously known as tetragonal-almandine-pyrope-phase (TAPP). Honors two scientists, Jeffrey W. Harris (b. 1940), School of Geographical and Earth Sciences, University of Glasgow, Scotland.