Siderite


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Related to Siderite: pyrite

siderite

(sĭd`ərīt) or

chalybite

(kăl`ĭbīt), a mineral, varying in color from brown, green, or gray to black and occurring in nature in massive and crystalline form. A carbonate of iron, FeCO3, it serves as an iron ore, especially in the British Isles. It is widely distributed, being found also in the United States, Europe, South America, and Australia.

Siderite

 

(also spathic iron, chalybite), a mineral, a carbonate of iron with the composition Fe[CO3]. Siderite contains 62.01 percent FeO and 37.99 percent CO2. Its composition often includes isomorphic admixtures of Mn and Mg, which replace iron; more rarely, Ca is present, as are Co and Zn. Siderite cystallizes in the trigonal system, forming rhombohedral, tabular, prismatic, or scalenohedral crystals; the last occur rarely. The mineral usually occurs as granular aggregates, sinters, concretions, spherulites, and earthy agglomerates; it forms deposits in the form of veins, strata, and irregularly shaped bodies. Siderite is yellowish white, gray or greenish gray and turns brown upon weathering. It has a hardness of 4.5 on Mohs’ scale and a density of 3,960 kg/m3.

Depending on the conditions of formation, siderite is classified as being of hydrothermal, sedimentary (infiltration and precipitation), or metamorphosed origin. During weathering and oxidation, siderite is usually converted into hydrogoethite or hydrohematite. Siderite is one of the most important minerals in iron ore.


Siderite

 

any of the iron class of meteorites, according to modern classification. Formerly, the designation “siderite” was applied to iron meteorites that consist almost wholly of nickel-iron.

siderite

[′sid·ə‚rīt]
(mineralogy)
FeCO3 A brownish, gray, or greenish rhombohedral mineral composed of ferrous carbonate; hardness is 4 on Mohs scale, and specific gravity is 3.9. Also known as chalybite; iron spar; rhombohedral iron ore; siderose; sparry iron; spathic iron; white iron ore.
References in periodicals archive ?
Also, the southern deposits are more polymetallic in composition, including such minerals as galena, sphalerite, pyrite, siderite, chalcopyrite, marcasite, bornite, and quartz.
2000): Geochemistry of early siderite cements from the Eocene succession of Whitecliff Bay, Hampshire Basin, U.
Massive siderite, much of it shot through with fine-grained manganese oxides and hematite, is a minor constituent of the gangue fillings of the ore veins (Zincken, 1825; Rumscheidt, 1926).
2004, "Cr(VI) reduction in aqueous solutions by siderite," J.
Siderite within the Barnsdall Formation of northeastern Oklahoma occurs in four varieties: (1) large nodules lacking a distinct central nucleus, concentrated in horizons bearing articulated crinoids; (2) small concretions with distinct skeletal nuclei consisting of infaunal bivalves and inarticulate brachiopods occurring in horizons relatively lacking in articulated crinoids and crinoid material; (3) large sideritized burrows occurring above crinoid horizons; and (4) concretions nucleated around former sites of soft tissue in large crinoids and productid brachiopods.
Further north, pyrite is rare, while siderite (Fe[CO.
Yet Wise patiently and seriously examined the specimens as a trained paleontologist, and concluded unequivocally that they were "inorganically precipitated iron siderite nodules and not fossil material at all.
The percentage of claystones, characteristically containing more or less abundant siderite spherules normally less than 1 millimeter in diameter, decreases from northwest to southeast, and the claystones are replaced by silty and sandy dark-gray shales.
Siderite decomposes in the presence of acid to form C[O.
Removal of paramagnetic minerals from non-ferrous metal ores, such as siderite or ilmenite from cassiterite;