Butianite
Butianite is an IMA-recognized mineral species in the sulfide class, with the chemical formula Ni₆SnS₂.
It crystallizes in the tetragonal crystal system (space group I4/mmm). It is a member of the Nuwaite structural group.
Key properties: specific gravity 7.62.
IMA symbol But, IMA status: approved, named in 2016.
Very late-stage, vapor-deposited, alteration product in veins and as mono-mineralic crack-filling material in igneous diopside in the Type B1 Ca-Al-rich inclusion (CAI) ACM-2 from the Allende CV3 carbonaceous chondrite.
It is found associated with Al-Ti-rich diopside, nuwaite, heazlewoodite, Ge-bearing Ni-Fe alloy, possibly monticellite.
The name commemorates the Chinese words “Bu Tian, ” meaning patching the sky, in allusion to this secondary mineral filling cracks in a primitive refractory inclusion in the early solar system.