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Brown Spar
Brown spar or ''brown-spar'' ()''Krivovichev V. G.'' Mineralogical glossary. Scientific editor :uk:Булах Андрій Глібович, A. G. Bulakh. — St.Petersburg: St.Petersburg Univ. Publ. House. 2009. — 556 p. — ISBN 978-5-288-04863-0 is a trivial name, trivial, partly obsolete name for at least ''four'' carbonate minerals that are relatively similar in composition: ankerite, Dolomite (mineral), dolomite (with varieties), magnesite (with varieties) and siderite,Bulletin of the United States National Museum. No.30. Published under the Directions of the Smithsonian Institution. — Washington: Government Printing Office, 1885. which have a characteristic dirty-brown hue due to the content of iron compounds, as well as an admixture of manganese oxide. As a consequence, many varieties of Dolomite (mineral), dolomite, colored brown or grey-brown by impurities, are also known as ''brown spar''. The name brown spar is both capacious and vividly descriptive, referring exclu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siderite
Siderite is a mineral composed of iron(II) carbonate (FeCO3). Its name comes from the Ancient Greek word (), meaning "iron". A valuable iron ore, it consists of 48% iron and lacks sulfur and phosphorus. Zinc, magnesium, and manganese commonly substitute for the iron, resulting in the siderite-smithsonite, siderite-magnesite, and siderite-rhodochrosite solid solution series. Siderite has Mohs hardness of 3.75 to 4.25, a specific gravity of 3.96, a white streak and a vitreous or pearly luster. Siderite is antiferromagnetic below its Néel temperature of that can assist in its identification. It crystallizes in the trigonal crystal system; crystals are rhombohedral in shape, typically with curved and striated faces. It also occurs in masses. Color ranges from yellow to dark brown or black, the latter being due to the presence of manganese. Siderite is commonly found in hydrothermal veins, and is associated with barite, fluorite, galena, and others. It is also a common ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |