An Etymological Dictionary of Astronomy and Astrophysics

1. A mineral composed of iron carbonate, FeCO₃, that is a valuable ore of → iron.
   
2. A category of → meteorites consisting mainly of → iron and → nickel, commonly referred to as Irons. There are 13 different chemical groups of siderites. These groups are defined based
   on the relative abundance of nickel, gallium, germanium, and iridium. Irons are also categorized by their structural type.

See also: → sidero-; → -ite.