Tochilinite

minerals

valleriite

pyrrhotite

troilite

Formula: 6(Fe0.9S).5[(Mg,Fe)(OH)2]
Sulphide, valleriite group
Specific gravity: 2.96 to 2.99
Hardness: 1 to 1½
Colour: Bronze-black
Environments

Plutonic igneous environments
Meteorites

Tochilinite occurs in sulphide-rich serpentinised ultramafic bodies, where it may be abundant, in diamond pipes and in some carbonaceous chondrite meteorites (HOM, Webmin).

Localities

At Bancroft, Ontario, Canada, tochilinite is associated with pyrrhotite, forsterite, clinohumite, hydromagnesite, graphite and calcite (HOM).

At the type locality, the Nizhnii Mamon Cu-Ni Deposit, Nizhnii Mamon Village, Upper Don River, Voronezh Oblast, Russia, tochilinite occurs as radiating aggregates of cylindrical acicular crystals, which may be hollow, to 1 cm, as paper-thin coatings, as felted masses and as clots (Mindat). It has been found in lizardite from drill cores (AM 57.1552). Associated minerals include troilite, pyrrhotite, sphalerite, calcite and lizardite (HOM ).

At Hunting Hill quarry, Maryland, tochinilite is found rarely as prismatic crystals or sprays to 1.1 cm on calcite (Minrec 36.5.444).

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