Rhodochrosite

Rhodochrosite
Rhodochrosite

Rhodochrosite from Sweet Home Mine, Alma, Colorado, USA
General
Category Mineral species
Chemical formula MnCO3
Strunz classification 05.AB.05
Identification
Molar mass 114.95 g/mol
Color Red to pink, Brown to yellow, gray to white
Crystal habit Massive to well crystalline
Crystal system Trigonal - Hexagonal Scalenohedral
Twinning on the {0112} uncommon
Cleavage on the [1011] perfect
Fracture uneven, conchoidal
Tenacity brittle
Mohs scale hardness 3.5-4
Luster Vitreous
Streak White
Diaphaneity Transparent to translucent
Specific gravity 3.5 to 3.7
Density 3.7 g/cm³
Optical properties Uniaxial (-)
Birefringence δ = 0.218
Pleochroism weak
Ultraviolet fluorescence None
References [1][2]
Pink is the most common color of Rhodochrosite. Specimen mined near Silverton, Colorado

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. The streak is white. Its Mohs hardness varies between 3.5 and 4. Its specific gravity is 3.5 to 3.7. It crystallizes in the trigonal system. The cleavage is typical rhombohedral carbonate cleavage in three directions. Crystal twinning often is present. It is transparent to translucent with refractive indices of =1.814 to 1.816, =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.

Rhodochrosite 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. Catamarca, Argentina has an old Incan silver mine that has produced fine stalactitic examples of rhodochrosite that are unique and very attractive. Cut cross-sections reveal concentric bands of light and dark rose colored layers. These specimens are carved and used for many ornamental purposes.[3]

Its main use is as an ore of manganese which is a key component of low-cost stainless steel formulations and certain aluminium alloys. Quality banded specimens are often used for decorative stones and jewelry. Due to its being relatively soft, and having perfect cleaveage, it is very difficult to cut, and therefore rarely found faceted in jewelry.

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.

Colorado officially named rhodochrosite as its state mineral in 2002 based on a proposal by a local high school (Platte Canyon High School in Bailey, Colorado). The reason for this lies in the fact that while the mineral is found worldwide, large red crystals are found only in a few places on earth, and some of the best specimens have been found in the Sweet Home Mine near Alma, Colorado.

The Alma King is the largest known rhodochrosite crystal; it was found in the Sweet Home Mine near Alma, Colorado. It is on display in the Denver Museum of Nature and Science.

The Incas believed that rhodochrosite is the blood of their former rulers, turned to stone, therefore it is sometimes called "Rosa del Inca" or "Inca Rose".[4][5]

Contents

Rhodochrosite and silver mining

Manganese 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.

See also

Manganoan Calcite

Footnotes

References



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Look at other dictionaries:

  • Rhodochrosite — Catégorie V : carbonates et nitrates[1] Alma King, le plus grand cristal de rhodochrosite connu …   Wikipédia en Français

  • Rhodochrosite — Rho do*chro site, n. [Gr. ro don the rose + ??? a coloring.] (Min.) Manganese carbonate, a rose red mineral sometimes occuring crystallized, but generally massive with rhombohedral cleavage like calcite; called also {dialogite}. [1913 Webster] …   The Collaborative International Dictionary of English

  • rhodochrosite — ● rhodochrosite nom féminin Carbonate naturel de manganèse, de couleur rose, rhomboédrique …   Encyclopédie Universelle

  • rhodochrosite — [rō΄də krō′sīt΄] n. [Ger rhodochrosit < Gr rhodochrōs, rose colored (< rhodon, rose: see RHODA) + chrōsis, a coloring < chrōs, color, akin to chrōma: see CHROME + Ger it, ITE1] a glassy pinkish to gray mineral, MnCO3, an ore of manganese …   English World dictionary

  • rhodochrosite — /roh deuh kroh suyt/, n. a mineral, manganese carbonate, MnCO3, commonly containing some iron and calcium, and usually rose red in color: a minor ore of manganese; manganese spar. Also called dialogite. [1830 40; < Gk rhodóchros rose colored… …   Universalium

  • rhodochrosite — rodochrozitas statusas T sritis chemija apibrėžtis Mineralas. formulė MnCO₃ atitikmenys: angl. manganspate; rhodochrosite rus. марганцовый шпат; родохрозит ryšiai: sinonimas – mangano špatas …   Chemijos terminų aiškinamasis žodynas

  • rhodochrosite — noun Etymology: German Rhodocrosit, from Greek rhodochrōs rose colored, from rhod + chrōs color more at chromatic Date: 1836 a rose red mineral consisting essentially of manganese carbonate …   New Collegiate Dictionary

  • rhodochrosite — noun A crystalline mineral composed mainly of manganese carbonate MnCO …   Wiktionary

  • rhodochrosite — [ˌrəʊdə(ʊ) krəʊsʌɪt] noun a mineral consisting of manganese carbonate, typically pink, brown, or grey. Origin C19: from Gk rhodokhrōs rose coloured + ite1 …   English new terms dictionary

  • rhodochrosite — rho·do·chro·site …   English syllables

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