Rough Optical Calcite with Inclusions / 1.5-2.5" AVG - 1 KILO LOT Menu Raw Crystals & Clusters has made it highly desirable

has made it highly desirable in jewelry for centuries

It was first discovered by and named for Canadian chemist and geologist Henry How in 1868

or simply black tourmaline

Pieces are randomly selected

Pieces measure approximately 14-16" (AVERAGE SIZE)

Rough Optical Calcite with Inclusions / 1.5-2.5" AVG - 1 KILO LOT Menu Raw Crystals & Clusters has made it highly desirableQuantity: 1 kilogram Average size range: 1. 5 to 2. 5 inches Optical calcite, also known as Iceland spar, is a special type of calcite that forms extremely clear and somewhat rectangular crystals. For centuries, sailors would use these crystals to help determine the direction of the sun on cloudy days for navigation.