Nimite

nimite

willemseite

trevorite

violarite

Images

Formula: (Ni,Mg,Al)6(Si,Al)4O10(OH)8
Phyllosilicate (sheet silicate), chlorite group, nickel-bearing mineral

Crystal System: Monoclinic
Specific gravity: 3.123 measured, 3.21 calculated
Hardness: 3
Streak: White
Colour: Yellowish green
Common impurities: Cr,Mn,Co,Ca,H2O
Environments

Metamorphic environments

Localities

At the type locality, the Bon Accord Ni deposit, Barberton, Mbombela Local Municipality, Ehlanzeni District Municipality, Mpumalanga, South Africa, nimite occurs in a small tabular body of nickeliferous serpentinite at the contact between quartzite and ultramafic rocks. Associated minerals include ferroan trevorite, violarite, millerite, willemseite and secondary reevesite and goethite. The nimite appears to have formed at about 730oC and less than 2 kbar pressure during thermal metamorphism, possibly of a nickel-rich meteorite. (AM 54.1739, HOM).

At the Clear Creek claim (Clear Creek Mine), Goat Mountain, San Benito county, California, USA, nimite has been identified in the silicate-carbonate rocks (MinRec 36.4.354).

At Hunting Hill Quarry, Rockville, Montgomery county, Maryland, USA, nimite has been confirmed. The single known specimen shows greenish blue fine-grained plates associated with titanite, clinozoisite and black calcite (MinRec 36.5.443).

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