Millerite
Millerite | ||
---|---|---|
Specific gravity 5.3–5.5 | | |
Other characteristics | brittle and becomes magnetic on heating | |
References | [2][3][4][5][6] |
Millerite or nickel blende is a nickel sulfide mineral, NiS. It is brassy in colour and has an acicular habit, often forming radiating masses and furry aggregates. It can be distinguished from pentlandite by crystal habit, its duller colour, and general lack of association with pyrite or pyrrhotite.
Paragenesis
Millerite is a common metamorphic mineral replacing pentlandite within serpentinite ultramafics. It is formed in this way by removal of sulfur from pentlandite or other nickeliferous sulfide minerals during metamorphism or metasomatism.
Millerite is also formed from sulfur poor
During metamorphism, sulfur and nickel within the olivine lattice are reconstituted into metamorphic sulfide minerals, chiefly millerite, during serpentinization and talc carbonate alteration. When metamorphic olivine is produced, the propensity for this mineral to resorb sulfur, and for the sulfur to be removed via the concomitant loss of volatiles from the serpentinite, tends to lower sulfur fugacity.
This forms disseminated needle like millerite crystals dispersed throughout the rock mass.
Millerite may be associated with heazlewoodite and is considered a transitional stage in the metamorphic production of heazlewoodite via the above process.
Economic importance
Millerite, when found in enough concentration, is a very important ore of nickel because, for its mass as a sulfide mineral, it contains a higher percentage of nickel than pentlandite. This means that, for every percent of millerite, an ore contains more nickel than an equivalent percentage of pentlandite sulfide.
Millerite forms an important ore constituent of the Silver Swan, Wannaway, Cliffs, Honeymoon Well, Yakabindie and Mt Keith (MKD5) orebodies. It is an accessory mineral associated with nickel laterite deposits in New Caledonia.
Occurrence
Millerite is found as a metamorphic replacement of
It is commonly found as radiating clusters of acicular needle-like crystals in cavities in sulfide rich
Millerite was discovered by
See also
References
- S2CID 235729616.
- ^ Mineralienatlas
- ^ http://rruff.geo.arizona.edu/doclib/hom/millerite.pdf Handbook of Mineralogy
- ^ http://www.mindat.org/min-2711.html Mindat
- ^ http://webmineral.com/data/Millerite.shtml Webmineral
- ISBN 0-471-80580-7
- ^ "Millerite". Cape Minerals. Retrieved 7 February 2017.
- .