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Formula: Cu+(Rh3+Pt4+)S4
Sulphide, carrollite subgroup,
thiospinel group,
spinel supergroup,
rhodium- and platinum-
bearing mineral
Crystal system: Isometric
Specific gravity: 6.66 calculated for the empirical formula
Hardness: 5
Environments
Plutonic igneous environments?
Ezochiite purportedly is a new mineral, approved in 2022. However, it has been suggested that
ezochiite is not a new mineral, but a rhodium-rich variety of
cuprorhodsite.
Localities
At the type locality, the Tomamae coast, Tomamae, Tomamae District, Rumoi Subprefecture, Hokkaidō Prefecture, Japan,
ezochiite, a platinum group mineral in the
thiospinel group was discovered. Additional specimens were found
later in the Shosanbetsu river, Ainusawa river and Obira coast, Hokkaido. Ezochiite crystallised in melt
pockets trapped in isoferroplatinum grains, occurring in the form
of anhedral grains less than 5 μm in length. Ezochiite is associated with sulphide minerals such as
braggite, cooperite,
torryweiserite and
chalcopyrite. It is opaque and has a metallic lustre with a bluish
grey colour in reflected light
(Journal of Mineralogical and Petrological Sciences 119(1)240304).
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