Rondorfite
Rondorfite is an IMA-recognized mineral species in the silicate class, with the chemical formula Ca₈Mg(SiO₄)₄Cl₂.
It crystallizes in the cubic crystal system (space group P1).
Key properties: specific gravity 3.03; Light amber streak; Vitreous luster.
IMA symbol Ron, IMA status: approved, named in 1997.
Found in metasomatized limestone xenoliths in leucite tephrite lava or ignimibrites. In burned spoil heaps from coal mines (Czech Republic).
It is found associated with Ettringite-thaumasite, mayenite, ternesite, cuspidine, larnite, “calcio-olivine”, tobermorite, portlandite, hydrocalumite, a member of the ellestadite series.
The mineral was named to honor Alice and Eugen Rondorf, two mineral collectors, who found the mineral with Bernd Ternes in 1979.