By Chisom Ibemere
Rhodochrosite is a mineral of manganese carbonate. It is rare in its pure state and is typically a rose-red colour but it can also be shades of pink to pale brown. It has white streaks and its Mohs hardness varies between 3.5 and 4.5. Its specific gravity is between 3.45 and 3.6. It crystallizes in the trigonal system, and cleaves with rhombohedral carbonate cleavage in three directions. Crystal twinning is often present.
Rhodochrosite may be mistaken with the manganese silicate, rhodonite, but is distinctly softer. Rhodochrosite occurs by the formation of the oxidation of manganese ore, and is seen in places like South Africa, China, and the Americas. It is officially listed as one of the National symbols of Argentina.
Rhodochrosite forms a complete solid solution series with iron carbonate. 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. This is the reason for the pink colorouration of rhodochrosite.
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Rhodochrosite occurrencance is seen in 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. Rhodochrosite that are banded are mined in Capillitas, Argentina.
Rhodochrosite is described first in 1813 in reference to a sample from Cavnic, Maramureş, present-day Romania. It’s name is gotten from the combination of Greek words rodon, meaning rose and chrosis which means coloring.
Rhodochrosite is majorly applied as an ore of manganese, a low key component of low-cost stainless steel formulations and certain aluminium alloys. The banded and quality specimens are often used for decorative purposes in stones and jewellery. As a result of its softness and perfect cleavage it is rarely found faceted in jewellery.
Manganese carbonate is extremely destructive to the process of amalgamation which is historically used in the concentration of silver ores, and which was often discarded on the mine dump.
