The name siderite comes from the Greek σίδηρος (sídyros) = iron. The color is yellow-brown, brown to black-brown. It is usually granular, lump, in kidney-shaped or grape-shaped aggregates. They form limited clutch-shaped crystals, often lens-shaped crystals. Previously, siderite used to be one of the main iron ores. It occurs on hydrothermal veins, forms sedimentary deposits or deposits in limestone. More info