Nabimusaite
A very rare potassium-calcium silicate-sulfate of Israel's Hatrurim rocks — namesake of its own group.
Intro adapted from Wikipedia (CC BY-SA).
Nabimusaite is an IMA-recognized mineral species in the silicate class, with the chemical formula KCa₁₂(SiO₄)₄(SO₄)₂O₂F.
It crystallizes in the hexagonal crystal system (space group R-3m). It is a member of the Nabimusaite structural group.
Key properties: Mohs hardness 5; specific gravity 3.119; White streak; Vitreous luster; optically uniaxial.
IMA symbol Nbm, IMA status: approved, named in 2012.
High-temperature syn-pyrometamorphic alteration of primary ye’elimite-larnite rocks during combustion events as a result of the reaction of potassium-enriched, sulfate-bearing melt with larnite and ellestadite.
It is found associated with Larnite, ye’elimite, brownmillerite, P-fluorellestadite, fluormayenite-fluorkyuygenite, gehlenite, ternesite, jasmundite, periclase, oldhamite, covellite.
The name refers to the village, Nabi Musa, near the locality that produced the first specimens.