Iolite 4-7mm Faceted Rondelle - 18 Inch hps_07232026 gray and brown banding and

gray and brown banding and dendritic patterns

Black Tourmaline is a black crystalline aluminum borosilicate mineral with occasional light gray inclusions that appear as flecks or veins

It is found around the world in many unusual natural formations including globes

the hole size

Composed mostly of tiger's eye

Iolite 4-7mm Faceted Rondelle - 18 Inch hps_07232026 gray and brown banding andIolite most commonly occurs in shades of blue to gray, violet or indigo. It displays a visual property called pleochroism, which means that it can appear to be different colors as it shifts in the light. According to Norse legend, Viking explorers used thin pieces of Iolite as the worlds first polarizing lens to help them determine the exact location of the sun for navigation.