Keplerite
Keplerite is an IMA-recognized mineral species in the phosphate class, with the chemical formula Ca₉(Ca₀.₅ ₀.₅)Mg(PO₄)₇.
It crystallizes in the hexagonal crystal system (space group R3c). It is a member of the Cerite structural group.
Key properties: specific gravity 3.122; Vitreous luster; optically uniaxial.
IMA symbol Kep, IMA status: approved, named in 2020.
Found in some pallasite and angrite meteorites. In brecciated, altered pyroxene paralava (fused sediments) by pyrometamorphism (Israel). An indicator of high-temperature environments characterized by extreme depletion of sodium.
It is found associated with Troilite-orthopyroxene vermicular intergrowths, olivine, Fe-Ni metal (meteorites); fluorapatite, maghemite, stanfieldite (Israel).
The mineral was named to honor Johannes Kepler (1571-1630), a prominent German naturalist, for his contributions to astronomy and crystallography.