All Sources -
Updated Media sources (1) About encyclopedia.com content Print Topic
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 streak; metallic lustre; crystals rare, and can be platy or tabular, but the mineral is usually massive or granular; no cleavage; magnetic; occurs in igneous rocks, e.g. gabbro or norite, as disseminated grains, and also in metamorphic contact zones in association with chalcopyrite and pyrite. Pyrrhotite was used formerly for the production of sulphuric acid.
More From encyclopedia.com
Edta , EDTA Ethylene diamine tetra‐acetic acid, a compound that forms stable chemical complexes with metal ions (i.e. a chelating agent). Also called versen… 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… Hornblende , Hornblende hornblende An important rock-forming silicate mineral and member of the amphiboles, particularly the calcium-rich monoclinic amphiboles; i… Wollastonite , enstatite (En) An important orthorhombic pyroxene (orthopyroxene, or opx) Mg2Si2O6 and end-member of an isomorphous series, the other end-member bein… ilmenite , ilmenite Mineral, FeTiO3; sp. gr. 4.5–5.0; hardness 5–6; trigonal; black; black to brownish-red streak; sub-metallic lustre; crystals normally thick… Periodic Table Of The Elements Chromium , chromium (krō´mēəm) [Gr.,=color], metallic chemical element; symbol Cr; at. no. 24; at. wt. 51.9961; m.p. about 1,857°C; b.p. 2,672°C; sp. gr. about…
You Might Also Like