RANCIÉITE
RANCIÉITE Ranciéite – (Ca,Mn2+)0.2(Mn4+,Mn3+)O2·0.6H2O – is a rarer oxide, a minor component of Mn ores, with 75.34% MnO2. It is classified in the Birnessite Group, in the Ranciéite-Takanelite Series, the two being isostructural. Macroscopically it can be confused with todorokite, but X-ray diffractograms are diagnostic, somewhat variable depending on the degree of hydration. The literature […]
RHODOCHROSITE
RHODOCHROSITE Rhodochrosite – MnCO3 – is a rarer carbonate. It is a very secondary ore of Mn and has many uses as a decorative stone, fetching high prices in the collector and ornamental stone market, but it is not suitable for stoning. Once exposed to the atmosphere, it can develop a thin black surface film […]