64g Optical Calcite Freeform TC2139 byssolite but was not widely known

but was not widely known until the 1970's partly because it has an unremarkable appearance in the field

Moscona Mine Yellow Fluorite

Dendritic opal pendant set in sterling silver

Some of the sphalerite crystals are small enough that they are able to show their semi-transparent orange color

Dimensions: 5x2x0

64g Optical Calcite Freeform TC2139 byssolite but was not widely known64g Optical Calcite Freeform Approx. Dimensions: 1. 25x1x2. 25 inches Approx. Weight: 64 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