Rhodonite

A brilliant pink or red colored mineral, rhodonite’s bright colors may be obscured by black marks, a result of oxidation. Rhodonite is formed mainly in manganese-bearing metamorphic rocks, especially marble and skarn, which were previously limestone. It is also found in sediments that have been altered by metasomatism (chemical change). Among the minerals with which rhodonite is most commonly associated are calcite, garnet and pyrite.

The English name of this mineral is derived from the Greek rhodon, meaning “rose,” this being a reference to its bright pink to reddish coloration. Rhodonite was confirmed as a distinct species in 1819. The main use of rhodonite is as an ornamental or semiprecious stone.

Crystals of rhodonite conform to the triclinic system of symmetry, and distinct individual specimens have a blocky, prismatic habit. Such formations are unusual, however, and those that do occur are rarely suitable for faceting because of their brittleness and sensitivity to heat. One of the key tests for this mineral is that when it is held in an open flame, it fuses easily and turns into a reddish glass.

When freshly extracted from the Earth, the surface of rhodonite may sometimes be discolored by unsightly black marks and veins of manganese oxide. However, these impurities can be easily removed by dabbing the surface of the stone with dilute hydrochloric acid. This removes the marks but does not damage the mineral, rhodonite itself being insoluble in acids.

Most rhodonite deposits in B.C. are in the form of lenses occurring with bedded chert or jasper. Very beautiful rose-pink material occurs on Saltspring Island and Vancouver Island , notably on Hill 60 and Cottonwood Creek. Other rhodonite bearing sedimentary rock formations are the Shoemaker formation near Keremeos, the Cache group from Tsitsutl Mt. (near Fort St. James) extending to Williams Lake; the Fennell formation (Clearwater to Barriere); the Cassiar area; Kaslo to Slocan area; and fine pink material with black patterns from Bella Coola area.

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