3.4" Calcite Crystal Cluster (Unusual Formation) - Norway

This is a unique, 3.4" wide cluster of calcite crystals that was collected from the Kjørholt mine near Porsgrunn, Norway. There are a variety of calcite formations on this specimen including small bladed crystals, large scalenohedral crystals and a rare crystal formation that the dealer referred to as "twin calcite". This crystal type was first discovered in 2009, with many of the specimens featuring micro-apophyllite crystals encrusting the calcite.

The base of the specimen has been stabilized with glue. Comes with an acrylic display stand.

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.
Kjørholt Mine, Brevik, Porsgrunn, Telemark, Norway
3.4 x 3.2"