Calcite

Sokolovskoe Mine (Sokolovskiy Mine), Rudny, Kostanay Region  Kazakhstan

Specimen size: 14.7 × 11.2 × 8.2 cm = 5.79” × 4.41” × 3.23”
Main crystal size: 4.5 × 2.5 cm = 1.77” × 0.98”