Manganese carbonate. Rhodochrosite is a mineral of the calcite series, its name being derived from the Greek rhodon, meaning "pink."

Crystal system Trigonal.

Appearance It occurs as semitransparent. rhombohedral crystals with poor luster, or as concretionary masses, sometimes with irregular, contorted veining. Normally a definite pink, itcan be faded pink or slightly orange. Chemical alteration turns it blackish or dull brownish.

Physical properties It has a low hardness of about 4. The density is usually 3.4-3.? g/cm“. The refractive indices are no 1.60, Du: 1.82. It has perfect rhombohedral cleavage.

Genesis Rhodochrosite ls tound in hydrothermal veins, but also in sedimentary deposits of chemical origin.

Occurrence It is quite a common mineral, especially in the United States. Argentina, Mexico, Namibia. Spain, Flomania, and the Soviet Union.

Despite its rather low hardness. this mineral is used as an ornamental material because of its pleasing color.

Appearance The massive material is characterized by a bright pink color, generally in distinct bands (as with agate and malachite), which may be curved or finely contorted, with narrow pale pink or whitish veinlng. Small slabs are used for mosaics. boxes, pots, and figurines. but the mineral is somewhat brittle. It is also made into necklace beads or other types of jewelry and recently, quite large, almost transparent crystals have yielded attractive, curved gems
Distinctive features It has a color similar to that of rhodonite. but is distinguished from the latter by its concretionary structure and by the fact that it is visibly attacked by hydrochloric acid. It ls also much less hard.

Occurrence The ornamental material mainly comes from Argentina, the United States (Colorado and Montana), Namibia. and the Soviet Union.

Value Somewhat low. Necklaces of transparent pieces are worth more, although the gem's relative lack of hardness can make it lose its polish easily.

Simulants and synthetics It is neither imitated nor produced synthetically.