millerite Mineral, NiS; sp. gr. 5.2–5.6; hardness 3.0–3.5; trigonal; brass-yellow and opaque; greenish-black streak; metallic lustre; crystals usually long, slender, acicular, and in radiating groups; cleavage perfect, rhombohedral; occurs as tufts of radiating fibres in cavities, and as replacement for other nickel minerals, also in veins carrying nickel minerals and other sulphides, and around some volcanoes as sublimation products. It is a minor ore of nickel and named after the British mineralogist W. H. Miller.
More From encyclopedia.com
Uraninite , uraninite (pitchblende) Mineral, UO2; sp. gr. from 8.5 when massive to 10 for unaltered crystals; hardness 5–6; cubic; it is brownish-black or grey-b… wolframite , wolframite Ore mineral for tungsten, with the formula (Fe,Mn)WO4; sp. gr. 7.0–7.5; hardness 5.0–5.5; monoclinic; grey-black to brownish-black; browni… Sphalerite , sphalerite (black jack, zinc blende) Mineral, ZnS; sp. gr. 3.9–4.1; hardness 3.5–4.0; cubic; colour variable, but commonly yellow, brown, or black, a… Stibnite , stibnite (antimonite, antimony glance) One of the main ore minerals for antimony, with the formula Sb2S3; sp. gr. 4.6; hardness 2.0–2.5; orthorhombic… Pyrrhotite , pyrrhotite Mineral, FeS; sp. gr. 4.6–4.7; hardness 3.5–4.5; hexagonal; bronzeyellow but darkens rapidly to reddishbrown on exposure; greyish-black st… Cuprite , cuprite (red copper ore) Mineral, Cu2O; sp. gr. 5.8–6.1; hardness 3.5–4.0 cubic; red to nearly black; brownish-red streak; adamantine to sub-metallic…
About this article
Updated About encyclopedia.com content Print Article
You Might Also Like