Siderite.

Siderite.

Siderite,  FeCO3  is an iron carbonate. It has an iron content of 48%, but as it is not found in such great quantities as other iron ores, and is more difficult to process, it has a lower economic value. The crystals are well defined, cream coloured, and rhomohedral. The associated pyrite crystals are much smaller and octahedral. The specimen is from the massive open cast mine in Lipez, Bolivia.