Variation in colour of rhodochrosite from Yakumo mine.

Abstract

The colour of rhodochrosite is pale light pink when pure, but commonly it is pale pink, dark pink, purple, reddish brown and brown in natural crystals. In the Yakumo mine, colour of rhodochrosite crystallizing in the early stage is pale or dark pink, or rarely purple, and the saturation is pale, while those crystallizing in the later stage are variable from reddish pink to reddish dark orange(brown) in colour, and the saturation is deep. It is remarkable that the former is almost free from iron component, whereas the latter always contains about 10 percent of FeO.