Silvery pink crystals of the rare Sn-mineral stannoidite from a Japanese locality (Akenobe Mine, Yabu City, Honshu Island, Japan) associated to golden chalcopyrite — Photo: David Hospital · CC BY-SA 4.0
Stannoidite
A five-element sulfide — copper, iron, zinc, tin and sulfur — 'tin-like' in structure.
Intro adapted from Wikipedia (CC BY-SA).
Stannoidite is an IMA-recognized mineral species in the sulfide class, with the chemical formula Cu₈(Fe,Zn)₃Sn₂S₁₂.
It crystallizes in the orthorhombic crystal system (space group I222). It is a member of the Stannoidite structural group.
Key properties: Mohs hardness 4; specific gravity 4.68; Dark brown-gray streak; Metallic luster.
IMA symbol Sta, IMA status: approved, named in 1968.
Found in hydrothermal Sn–Cu sulfide deposits.
It is found associated with Chalcopyrite, galena, tetrahedrite, stannite, cassiterite, siderite, quartz (Konjo mine, Japan); hemusite, enargite, luzonite, colusite, reniérite, tennantite.
The name refers to its physical and chemical similarity to stannite.