Black metallic platy intergrown crystal of mathiasite and lindsleyite, two very rare minerals from the TL in Bultfontein, South Africa (Bultfontein Mine, Kimberley, Baard District, Northern Cape Province, South Africa). Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Mathiasite
Mathiasite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula (K,Ba,Sr)(Zr,Fe)(Mg,Fe)₂(Ti,Cr,Fe)₁₈O₃₈.
It crystallizes in the hexagonal crystal system (space group R-3). It is a member of the Crichtonite structural group.
Key properties: specific gravity 4.39; Metallic luster; optically uniaxial.
IMA symbol Mts, IMA status: approved, named in 1982.
A primary mantle-derived phase found in heavy-mineral concentrates from metasomatized kimberlite (South Africa).
It is found associated with Lindsleyite, olivine, diopside, phlogopite, Ce-bearing barite, Nb–Cr rutile, Mg–Cr spinel, ilmenite, perovskite, titanite (South Africa).
The mineral was named to honor Professor Frances Celia Morna Mathias (1913–), University of Cape Town, Cape Town, South Africa, for her contributions to studies of mantle-derived rocks.