Crowningshieldite
Crowningshieldite is an IMA-recognized mineral species in the sulfide class, with the chemical formula (Ni₀.₉Fe₀.₁)S.
It crystallizes in the hexagonal crystal system (space group P6_3/mmc). It is a member of the Nickeline structural group.
Key properties: Mohs hardness 3–3.5; specific gravity 5.47; Metallic luster.
IMA symbol Csh, IMA status: approved, named in 2018.
Part of a multiphase inclusion in a gem-quality, colorless, type IIa (containing less than ~5 ppm N) diamond from a kimberlite pipe.
It is found associated with Diamond, magnetite-magnesioferrite, hematite, graphite.
The mineral was named to honor G. Robert Crowningshield (1919-2006), who at the Gemological Institute of America (GIA) for more than 50 years.
Index entry. This entry combines official IMA/RRUFF species data with published physical-property data — a full written entry hasn’t been published yet.
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