Millerite

Mar 21, 2007 10:03:11

Formula: NiS System: Trigonal Colour: Pale brass-yellow, with ... Lustre: Metallic Hardness: 3 - 3½ Name: Named after the English mineralogist, W. H. Miller (1801-1880), who first studied the crystals. Commonly found as radiating and jack-straw clusters of shiny metallic acicular crystals, pale brass-yellow with an iridescent tarnish. Classification of Millerite IMA status: Valid - first described prior to 1959 (pre-IMA) - "Grandfathered" Strunz 8th edition ID: 2/C.21-30 2 : Sulphides C : Sulphides with metal: sulphur, selenium and tellurium = 1:1 21 : Millerite series Dana 7th edition ID: 2.8.16.1 Dana 8th edition ID: 2.8.16.1 2 : SULFIDES 8 : AmXp, with m:p = 1:1 Hey's CIM Ref.: 3.11.3 3 : Sulphides, Selenides, Tellurides, Arsenides and Bismuthides (except the arsenides, antimonides and bismuthides of Cu, Ag and Au, which are included in Section 1) 11 : Sulphides etc. of Ni mindat.org URL: http://www.mindat.org/min- 2711.html Please feel free to link to this page. Type Occurrence of Millerite Type Locality: Jáchymov (St Joachimsthal), Ostrov, Krusné Hory Mts (Erzgebirge), Karlovy Vary Region, Bohemia (Böhmen; Boehmen), Czech Republic Year of Discovery: 1845 Occurrences of Millerite Geological Setting: A low-temperature mineral which occurs in sulfidic limestones and dolostones, and as a late-forming mineral in nickel sulfide deposits. Physical Properties of Millerite Lustre: Metallic Diapheny (Transparency): Opaque Colour: Pale brass-yellow, with an iridescent tarnish, and greenish-grey. Streak: Greenish black. Hardness (Mohs'): 3 - 3½ Hardness (Vickers): VHN20=179(20) kg/mm2 Hardness Data: Measured Tenacity: Brittle Cleavage: Perfect Perfect on {10-11} and {01-12}. Fracture: Hackly Density (measured): 5.3 - 5.5 g/cm3 Density (calculated): 5.37 g/cm3 Crystallography of Millerite Crystal System: Trigonal Class (H-M): 3m - Ditrigonal Pyramidal Space Group: R3m Cell Parameters: a = 9.62Å, c = 3.149Å Ratio: a:c = 1 : 0.327 Unit Cell Volume: V 252.38 ų (Calculated from Unit Cell) Z: 9 Morphology: Acicular crystals in radiating or jack- straw clusters; also massive.