Nickel sulfide forming distinctive hair-like golden needle crystals. Named after mineralogist William Hallowes Miller. Color: Brass-yellow, bronze. Luster: Metallic. Streak: Greenish-black. Cleavage: Good in two directions. Hardness: 3-3.5. Transparency: Opaque. Crystal system: Hexagonal Trigonal. Chemical formula: NiS. Specific gravity: 5.5. Formation: Forms in low-temperature hydrothermal veins and in cavities in carbonate rocks and coal measures. Common geological settings: Germany, Canada, Wales, USA; found in limestone cavities and coal measures. Common look-alikes and related entries: Pyrite, Chalcopyrite, Pyrrhotite.
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These authoritative resources support category-level nomenclature, terminology, identification methods, and safety. When a specimen-specific safety warning appears, the public-health source listed here directly supports that precaution. They are not line-by-line citations for every other property on this entry, and natural specimens vary.
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Last updated
2026-03-30T14:37:52.040231+00:00
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IMA–CNMNC List of Mineral Names — International Mineralogical Association. Official mineral-name, nomenclature, and classification records.
Mineral ID Key — Mineralogical Society of America. Physical-property identification methods, repeat-testing guidance, and limitations.
Nickel sulfide forming distinctive hair-like golden needle crystals. Named after mineralogist William Hallowes Miller.
How can you identify Millerite?
Compare several properties rather than relying on colour alone. This entry records colour: Brass-yellow, bronze; lustre: Metallic; streak: Greenish-black; Mohs hardness: 3-3.5; cleavage: Good in two directions; crystal system: Hexagonal Trigonal; transparency: Opaque. Confirm an important identification with additional field tests or qualified laboratory work.
How does Millerite form?
Forms in low-temperature hydrothermal veins and in cavities in carbonate rocks and coal measures.
Where is Millerite commonly found?
Germany, Canada, Wales, USA; found in limestone cavities and coal measures.
What is Millerite commonly confused with?
Millerite may be confused with Pyrite, Chalcopyrite, Pyrrhotite. Compare multiple diagnostic properties because colour and surface appearance can overlap.
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