| 词条 | Rhodochrosite | ||||||
| 释义 |
| name = Rhodochrosite | category = Carbonate minerals | image = Rhodochrosite-Pyrite-Calcite-219228.jpg | caption = | formula = MnCO3 | molweight = 114.95 g/mol | strunz = 5.AB.05 | system = Trigonal | class = Hexagonal scalenohedral ({{overline|3}}m) H-M symbol: ({{overline|3}} 2/m) | symmetry = R{{overline|3}}c | unit cell = a = 4.777, c = 15.67 [Å]; Z = 6 | color = Pink, rose-red, cherry-red, yellow, yellowish gray, cinnamon-brown, may be banded | habit = Rhombohedral and scalenohedral crystals; also commonly bladed, columnar, stalactitic, botryoidal, granular or massive | twinning = On {10{{overline|1}}2} as contact and lamellar | cleavage = On {10{{overline|1}}1} perfect; parting on {10{{overline|1}}2} | fracture = Uneven, conchoidal | tenacity = Brittle | mohs = 3.5-4 | luster = Vitreous to pearly | polish = | refractive = nω = 1.814 - 1.816 nε = 1.596 - 1.598 | opticalprop = Uniaxial (-) | birefringence = δ = 0.218 | dispersion = | pleochroism = weak | fluorescence= None | absorption = | streak = White | gravity = 3.7 | density = | melt = | fusibility = | diagnostic = | solubility = | diaphaneity = Transparent to translucent | other = | references = [1][2][3] }} Rhodochrosite is a manganese carbonate mineral with chemical composition MnCO3. In its (rare) pure form, it is typically a rose-red color, but impure specimens can be shades of pink to pale brown. It streaks white, and its Mohs hardness varies between 3.5 and 4. Its specific gravity is between 3.5 and 3.7. It crystallizes in the trigonal system, and cleaves with rhombohedral carbonate cleavage in three directions. Crystal twinning often is present. It is transparent to translucent with refractive indices of nω=1.814 to 1.816, nε=1.596 to 1.598. It is often confused with the manganese silicate, rhodonite, but is distinctly softer. Rhodochrosite forms a complete solid solution series with iron carbonate (siderite). Calcium, (as well as magnesium and zinc, to a limited extent) frequently substitutes for manganese in the structure, leading to lighter shades of red and pink, depending on the degree of substitution. It is for this reason that the most common color encountered is pink. Occurrence and discoveryRhodochrosite occurs as a hydrothermal vein mineral along with other manganese minerals in low temperature ore deposits as in the silver mines of Romania where it was first found. Banded rhodochrosite is mined in Capillitas, Argentina. It was first described in 1813 in reference to a sample from Cavnic, Maramureş, present-day Romania. According to Dimitrescu and Radulescu, 1966 and to Papp, 1997, this mineral was described for the first time in Sacaramb, Romania, not in Cavnic, Romania. The name is derived from the Greek word ῥοδόχρως meaning rose-colored{{citation needed|date=August 2016}}. UseIts main use is as an ore of manganese, which is a key component of low-cost stainless steel formulations and certain aluminum alloys. Quality banded specimens are often used for decorative stones and jewelry. Due to its being relatively soft, and having perfect cleavage, it is very difficult to cut, and therefore rarely found faceted in jewelry. It is also typically used to make other desirable gems. Rhodochrosite and silver miningManganese carbonate is extremely destructive to the amalgamation process used in the concentration of silver ores, and so until quality mineral specimens became highly sought after by collectors, they were often discarded on the mine dump! Culture{{stereo image|image = Rhodochrosite3d.jpg |caption = Small Rhodochrosite specimen featured in a mineral kit, from Wuton mine, Guangxi prov, China. |width = 500 |height = 200 }} Rhodochrosite is Argentina's "national gemstone".[4][5] Colorado officially named rhodochrosite as its state mineral in 2002.[6] Large specimens have been found in the Sweet Home Mine near Alma, Colorado. It is sometimes called "Rosa del Inca", "Inca Rose" or Rosinca.[7] GallerySee also
References1. ^Handbook of Mineralogy 2. ^Rhodochrosite data on Mindat 3. ^Rhodochrosite data on Webmineral 4. ^{{cite web|url=http://www.ecolo.mrecic.gov.ar/content/piedra-nacional-la-rodocrosita|title=Piedra nacional: la Rodocrosita|publisher=Embassy of the Argentine Republic in the Colombian Republic|accessdate=7 October 2013|language=Spanish}} 5. ^{{cite web|url=http://www.pagina12.com.ar/diario/placer/16-12298-2002-11-09.html|title=La piedra argentina|author=Moreno, María|publisher=Página/12|date=9 November 2002|accessdate=7 October 2013|language=Spanish}} 6. ^{{cite web |url=http://www.colorado.gov/dpa/doit/archives/history/symbemb.htm#Mineral |title=Colorado State Archives; Symbols & Emblems |accessdate=2 February 2012}} 7. ^{{cite web|url=http://stoneplus.cst.cmich.edu/Rhodochrosite.htm|title=Rhodochrosite|author=R. V. Dietrich|date=2005-07-16|accessdate=2007-08-15}}
5 : Carbonate minerals|Manganese minerals|Symbols of Colorado|Trigonal minerals|National symbols of Argentina |
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