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