Calcite

St. Andreasberg mining area, Goslar District, Harz, Lower Saxony/Niedersachsen  Germany

Specimen size: 12.3 × 7 × 4.2 cm = 4.84” × 2.76” × 1.65”
Main crystal size: 5.4 × 2.4 cm = 2.13” × 0.94”