Siderite

Bollnbach Mine, Herdorf, Siegerland, Rhineland-Palatinate/Rheinland-Pfalz  Germany

Specimen size: 14.5 × 12 × 3.5 cm = 5.71” × 4.72” × 1.38”
Main crystal size: 4.5 × 2.7 cm = 1.77” × 1.06”