Calcite

La Sambre Quarry, Landelies, Montigny-le-Tilleul, Hainaut Province, Wallonia Region  Belgium

Specimen size: 9.8 × 7.9 × 6.1 cm = 3.86” × 3.11” × 2.40”
Main crystal size: 4.1 × 2.7 cm = 1.61” × 1.06”