My periodic table poster is now available! Siderite. Description from the source: Siderite (Fe+2 CO3 trig.), Bad Ems, Germany. Cleavaged masses, typic. 3,6x2x2 cm the bigger; 36 g all. Source: Simone Citon Contributor: John Gray Acquired: 30 September, 2008 Text Updated: 1 October, 2008 Price: Trade Size: 1.4" Composition: FeCO3