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
Lindsleyite
Lindsleyite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula (Ba,Sr)(Zr,Ca)(Fe,Mg)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 4.63; Metallic luster; optically uniaxial.
IMA symbol Ldy, IMA status: approved, named in 1982.
A mantle-derived phase in veinlets in metasomatized kimberlite (South Africa).
It is found associated with Mathiasite, phlogopite, perovskite, chromian diopside, potassian richterite, Nb–Cr rutile, Mg–Cr–Nb ilmenite, chromian spinel (South Africa).
The name refers to Professor Donald Hale Lindsley (1934–), State University of New York, Stony Brook, New York, USA, for his work in high-pressure petrology.