Calcite

Campomorto Quarry, Pietra Massa, Montalto di Castro, Viterbo Province, Lazio  Italy

Specimen size: 11.5 × 9 × 8.2 cm = 4.53” × 3.54” × 3.23”
Main crystal size: 3.6 × 3.6 cm = 1.42” × 1.42”