2.8" Red-Orange Stilbite Crystal Cluster with Calcite - Peru
This is a gorgeous mineral association that was collected from Peru. It features red-orange stilbite crystal clusters that formed in association with calcite. It's likely that this specimen is a part of a zeolite pocket find between 2006-2007 in Peru.
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.
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.