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Rhodochrosite - Occurrence, Properties, and Distribution

Rhodochrosite is a manganese carbonate mineral that crystallizes in the trigonal system. It is a member of calcite group of minerals. The mineral was first discovered in 1800 from the Cavnic (Kapnik), Maramures, Romania. It was named from the Greek word rhodon and chrosis, which mean rose and color, respectively.

Properties of Rhodochrosite

The following are the key properties of Rhodochrosite:

  • Cell Data
    • Space Group: R3c (synthetic)
    • a = 4.777
    • c = 15.67
    • Z = 6
  • Crystal Data
    • Hexagonal
    • Point Group: 3 2/m
    • Crystals are rhombohedra {1011} or scalenohedra {2131}, to 12 cm, modified by {0001}, {1010}, {1120}, with several other forms, may be rounded or saddle-shaped. Commonly in bladed aggregates, columnar, stalactitic, botryoidal, compact granular, massive
    • Twinning: On {1012}, contact and lamellar, then flattened
    • X-ray Powder Pattern: 2.84 (100), 3.66 (35), 1.763 (35), 1.770 (30), 2.172 (25), 2.000 (25), 2.39 (20)
  • Chemical Composition
    Elements Content 1 Content 2
    MnO 60.87 61.71
    CO2 38.26 38.29
    FeO 0.77
    CaO 0.51
    MgO trace
    Total 100.41 100.00
  • Optical Properties
    • Optical Class: Uniaxial (–)
    • Pleochroism: Faint
    • Absorption: O > E
    • ω = 1.810
    • ε = 1.597
  • Estimated Properties
    Electron density Bulk density (electron density)=3.53 g/cm3
    note: Specific gravity of Rhodochrosite =3.69 g/cm3
    Photoelectric PERhodochrosite = 12.46 barns/electron
    U= PERhodochrosite x ρElectron density= 44 barns/cm3
    Fermion index Fermion index = 0.001
    Boson index = 0.99
    Radioactivity
    Rhodochrosite is not radioactive

How to Identify Rhodochrosite

Rhodochrosite is a non-fluorescent mineral that occurs in brown, yellowish gray, rose red, red and pinkish red colors. It has a perfect cleavage, translucent to subtranslucent appearance, vitreous luster and white streak. Its fractures are very brittle producing small, conchoidal fragments. It can be observed in grape-like rounded forms, columnar forms and massive granular forms. The relative hardness of rhodochrosite is 3, and its density is 3.69 g/cm3.

Global Distribution

Rhodochrosite is distributed in the following places:

  • Cavnic (Kapnikb´anya) and Herja (Kisb´anya), Baia Mare (Nagyb´anya) district, Romania
  • Wolf mine, near Herdorf, Westphalia, Germany
  • Vuoriyarvi carbonatite complex and the Kovdor massif, Kola Peninsula, Russia
  • Mont Saint-Hilaire, Quebec, Canada
  • Emma mine, Butte, Silver Bow Co., Montana, USA
  • Home Sweet Home mine, Alma,Colorado
  • Park Co., Climax mine, Colorado
  • Lake Co., in the Sunnyside mine, near Silverton,Colorado
  • San Juan Co., and the Mountain Monarch mine, Ouray Co,Colorado
  • Cananea, Sonora, and Santa Eulalia, Chihuahua, Colorado
  • Huallap´on mine, Pasto Bueno, Ancash Department, and in the Uchuc-Chacua deposit, Cajatambo Province, Peru
  • Province, Peru
  • Capillitas mine, San Luis, Catamarca Province, Argentina
  • Hotazel and N’Chwaning mines, near Kuruman, Cape Province, South Africa
  • Inakuraishi and Yakumo mines, Hokkaido, Japan

Occurrence of Rhodochrosite and Useful Mineral Association

Rhodochrosite occurs in metamorphic deposits, carbonatites, sediments and as a primary mineral in low- to moderate-temperature hydrothermal veins. It is closely associated with hausmannite, alabandite, garnet, rhodonite, hubnerite, sphalerite, tetrahedrite, pyrite, quartz, barite, fluorite, dolomite, siderite and calcite.

References

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