Optical Calcite Freeform TC2017 septarian cube Northern Siberia

Northern Siberia

3" Specularite Slab

Hyalite doesn't have the same internal structure of tiny spheres of silicon dioxide that cause precious opals to have brilliant displays of color

Green Aventurine Skull Carving

Optical Calcite Freeform TC2017 septarian cube Northern SiberiaOptical Calcite Freeform Approx. Dimensions: 2. 5 x 1. 75 x 3 inches Approx. Weight: 420 grams Locality: Maharashtra, India Optical calcite is also referred to as Iceland Spar because of its first discovery in Eskifjord, Iceland. It is typically colorless, and exhibits the optical phenomenon of double refraction where an object viewed through the calcite will appear doubled. Double refraction, or birefraction, is also called birefringence and is also