Steel grey metallic aggregates of the very rare Pt-Cu mineral hongshiite from the type locality in Hongshila Pt-Pd deposit in China. Analyzed by the former owner of the specimen. Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY 4.0
Hongshiite
Hongshiite is an IMA-recognized mineral species in the native element class, with the chemical formula PtCu.
It crystallizes in the hexagonal crystal system (space group R-3m).
Key properties: Mohs hardness 4; specific gravity 15.71; Black streak; Metallic. Anisotropism: Weak to moderate, dull gray to dull reddish brown; copery brown to bright blue luster.
IMA symbol Hng, IMA status: approved, named in 1974.
Found in an actinolized diopside-type of platinum deposit (China); in high-grade hematitic veins in itabirite, typically rimmed by platinum from which copper has been leached (Brazil).
It is found associated with Cooperite, sperrylite, vysotskite, isomertieite, magnetite, bornite, polydymite, diopside, actinolite, epidote (China); sperrylite, isomertieite, atheneite.
The name refers to its occurrence near Hongshi village, China.