Millerite 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
2 Economic importance
4 See also
6 External links
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 olivine cumulates by
Millerite is thought to form from sulfur and nickel which
exist in pristine olivine in trace amounts, and which are driven out
of the olivine during metamorphic processes. Magmatic olivine
generally has up to ~4000 ppm Ni and up to 2500 ppm S within
the crystal lattice, as contaminants and substituting for other
transition metals with similar ionic radii (Fe2+ and Mn2+).[citation
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 concomittant
loss of volatiles from the serpentinite, tends to lower sulfur
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.
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.
Lustrous mass of intergrown millerite needles from Kalgoorlie, Western
Australia. (size: 3.9 x 3.5 x 2.2 cm)
Millerite is found as a metamorphic replacement of pentlandite within
the Silver Swan nickel deposit, Western Australia, and throughout the
many ultramafic serpentinite bodies of the Yilgarn Craton, Western
Australia, generally as a replacement of metamorphosed pentlandite.
There is one known occurrence of millerite in South Africa, near
Pafuri in the Transvaal. The deposit has never been commercially
It is commonly found as radiating clusters of acicular needle-like
crystals in cavities in sulfide rich limestone and dolomite or in
geodes. It is also found in nickel-iron meteorites, such as CK
Millerite was discovered by
Wilhelm Haidinger in 1845 in the coal
mines of Wales. It was named for British mineralogist William Hallowes
Miller. The mineral is quite rare in specimen form, and the most
common source of the mineral is in the Halls Gap area of Lincoln
County, Kentucky in the United States.
List of minerals
List of minerals
List of minerals named after people
Nickel Mines, Pennsylvania
^ http://rruff.geo.arizona.edu/doclib/hom/millerite.pdf Handbook of
^ http://www.mindat.org/min-2711.html Mindat
^ http://webmineral.com/data/Millerite.shtml Webmineral
^ Hurlbut, Cornelius S.; Klein, Cornelis, 1985, Manual of Mineralogy,
20th ed., pp. 279-280, ISBN 0-471-80580-7
^ "Millerite". Cape Minerals. Retrieved 7 February 2017.
^ Geiger, T.; Bischoff, A. (1995). "Formation of opaque minerals in CK
chondrites". Planetary and Space Science. 43 (3–4): 485–498.
Wikimedia Commons has media related to Millerite.
University of Kentucky, Kentucky Geological Survey, Sulfide Minerals