White crystal aggregates of the very rare calcium silicate mineral rustumite from a locality in Mexico (Negra Mine, Maconi, Cadereyta Municipality, Queretaro, Mexico). Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Rustumite
Rustumite is an IMA-recognized mineral species in the silicate class, with the chemical formula Ca₁₀(Si₂O₇)₂(SiO₄)(OH)₂Cl₂.
It crystallizes in the monoclinic crystal system (space group C2/c).
Key properties: specific gravity 2.94; optically biaxial.
IMA symbol Rtm, IMA status: approved, named in 1964.
Found in limestones between two ring dikes, developed during a metamorphic period in which H2O: CO 2 in the vapor phase was relatively high (Kilchoan, Scotland).
It is found associated with º Akermanite, merwinite, larnite, spurrite, rankinite, kilchoanite (Kilchoan, Scotland).
The name refers to Rustum Roy (1924{), experimental petrologist and materials scientist, Pennsylvania State University, University Park, Pennsylvania, USA.