7.6" Pink-Peach Stilbite and Calcite Crystal Association - India

Calcite, CaCO3, is a carbonate mineral and the most stable polymorph of calcium carbonate. The other polymorphs are the minerals aragonite and vaterite. Calcite crystals are trigonal-rhombohedral, though actual calcite rhombohedra are rare as natural crystals. However, they show a remarkable variety of habits including acute to obtuse rhombohedra, tabular forms, and prisms. Calcite exhibits several twinning types adding to the variety of observed forms. It may occur as fibrous, granular, lamellar, or compact. Cleavage is usually in three directions parallel to the rhombohedron form.

Stilbite is a tectosilicate mineral of the zeolite group that is commonly found in zeolite deposits. Crystals often form flowery bowtie or hourglass-shaped structures and come in a variety of colors. Some of the most beautiful colorations are the pink or peach tints.