Details of Siderite crystals, var. Spharosiderite Former private collection - Height: 9.2 cm - Width: 6.1 cm- 222 g - (1)

Siderite is a mineral belonging to the calcite group. Siderite is a mineral composed of ferrous carbonate (FeCO3). This iron carbonate mineral typically forms from hydrothermal veins, often together with minerals such as barite and fluorite. It is also common in clays and sandstones, forming concretions that can preserve fossils. In sedimentary rocks, siderite usually develops at shallow depths, its composition reflecting the surrounding sedimentary environment. Notably, the oxygen isotopes in spheroidal siderite, a soil-bound type, serve as records of the composition of meteoric water shortly after deposition, providing valuable insights into past climates.