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www.mineralgallery.co.za Minerals K-O |
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Millerite |
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Name
Millerite
Chemistry
NiS
Uses
Mineral specimen
Color
Bronze, gray, greenish grey to brass yellow
Hardness
3 - 3.5
Specific gravity
5.3 - 5.5
Crystals
Trigonal
Accompanied by:
Bravoite, Calcite, Chalcopyrite, Dolomite, Fluorite, Grossular, Pyrrhotite, Quartz
Fracture
Uneven
Luster
Metallic
Cleavage
Perfect
Streak
Black to dark green
Similar to:
Lapieite, Mückeite, Zlatogorite
Origin of name from mineralogist, William Hallowes Miller (1801-1880), first studier of crystals. It's also called "Capillary Pyrite", because of its brassy yellow color ( that is almost Pyrite colored).
Millerite forms fine acicular crystals, that look like hair-like fibers aggregated into sprays. Extremely rare mineral in igneous breccia cavities. Millerite forms long brassy fibers making very rare and aesthetic specimens. It becomes dulled or green as it alters to other nickel minerals such as Bravoite, Honessite, and Violarite.
Millerite's formation is mainly in limestone and hydrothermal replacement deposits and dolomite cavities. Found as radiating and jack-straw clusters of shiny metallic acicular crystals, pale brass-yellow with an iridescent tarnish.
