Rhodochrosite


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rhodochrosite

[‚rōd·ə′krō‚sīt]
(mineralogy)
MnCO3 A rose-red to pink or gray mineral form of manganese carbonate with hexagonal symmetry but occurring in massive or columnar form; isomorphous with calcite and siderite, has a hardness of 3.5-4 on Mohs scale, and a specific gravity of 3.7; a minor ore of manganese.

Rhodochrosite

 

(also manganese spar), a mineral of the carbonate class with the chemical composition MnCO3. It contains 61.71 percent MnO and 38.29 percent CO2, as well as admixtures of Fe, Mg, Zn, and sometimes Co. Rhodochrosite crystallizes in the trigonal system to form massive granular aggregates or incrustations. Crystals (usually rhombohedral) are rare. Rhodochrosite is pink, red, or greenish gray with a vitreous luster. It has a hardness of 3.5–4 on Mohs’ scale and a density of 3,600–3,700 kg/m3.

Rhodochrosite often occurs in hydrothermal sulfide veins and metasomatic deposits in association with, for example, rhodonite, manganese garnet, and hausmannite. Sedimentary rhodochrosite deposits are of commercial importance. The largest rhodochrosite deposits are located in the USSR, in the Northern Urals, and in the USA, in Butte, Mont. Rhodochrosite is used as a raw material in the smelting of ferromanganese and as an additional charge in the smelting of cast iron and steel; it is also used in the chemical industry.

References in periodicals archive ?
White, pink and brown grains of rhodochrosite were found rarely with the manganese ores of the Ilfeld-Mangan mine in Silberbachtal (Rumscheidt, 1926; Sansoni, 1971).
During the 2015 Tucson gem shows, gem dealer Mark Kaufman (Kaufman Enterprises, San Diego, California, USA) had some rough and cut transparent rhodochrosite from another locality: Brazil.
The primary hydrothermal stages could be subdivided into three stages, namely, (1) the early stage characterized by the assemblages of quartz + pyrite veins (Figure 6(a)), (2) the main ore stage characterized by galena + sphalerite + chalcopyrite + fluorite + rhodochrosite + multiple Ag-bearing sulfides (Figures 6(b)-6(e)), and (3) the late stage characterized by quartz + calcite + dolomite veins (Figure 6(f)).
Visitors to the exhibition were greeted, just inside the entrance, by four aesthetic cabinet specimens in individual glass cases: a rhodochrosite from the Sweet Home mine, Colorado; a green fluorite from Riemvasmaak, South Africa; a native gold from the Eagle's Nest mine, California; and an amethyst crystal group from the Anahi mine, Bolivia.
The first step, the Micro-Mineral Resurfacing Treatment, combines the power of natural sapphire crystals with semi-precious gemstones including malachite, smithsonite and rhodochrosite extract.
a thumbnail-size rhodochrosite specimen, whose photo fills a whole page, which could pass for the product of a very good day at Silverton, Colorado in the 1970s (the author writes that he "spent a lot of time hoping to find more [such rhodochrosite] ...
He conducted specimen mining operations at a number of localities throughout the west, including Colorado for rhodochrosite, Idaho for barite, and his home state of Nevada for a variety of minerals.
First, Ramos and Burillo had splendid specimens of rhodochrosite taken a year or so ago from the Manuelita mine, Yauli Province, Lima Department.
In the text Wiedenbeck lingers on some of these excitements, and offers personal angles on them: for one, there's a good account of the Sweet Home Rhodochrosite fever that came to town in 1993, and later, echoing it, comes the story of Wiedenbeck's at last buying, from Bryan Lees in 2002, the (barely affordable) Sweet Home rhodochrosite specimen of his dreams.
The Wyndham pit yielded manganese oxide minerals, including well-crystallized specimens of twinned black hausmannite crystals and also some attractive specimens of pink rhodochrosite (collected by Sir Arthur Russell in the 1930s).
He contributed two articles to the Mineralogical Record: one on rhodochrosite in 1971 and the other (with Richard Kosnar) on the minerals of the Colorado mineral belt in 1976.