RHODHOCROSITE

Origin Argentina

free form cab
highly polished
Natural Rhodochrosite

Beautiful watermelon - Color
Treatment-NONE

Diaphaneity, Transparent to translucent. Specific gravity, 3.7. Optical properties, Uniaxial (-). Refractive index, nω = 1.814 - 1.816 nε = 1.596 - 1.598. Birefringence, δ = 0.218. Pleochroism, weak. Ultraviolet fluorescence, None. References. Rhodochrosite is a manganese carbonate mineral with chemical composition MnCO3.

Crystal system‎: ‎Trigonal

Mohs scale hardness‎: ‎3.5-4

Crystal class‎: ‎Hexagonal scalenohedral (3m); ...

Optical properties‎: ‎Uniaxial (-)

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.