Iolite 10mm Round A Grade - 15-16 Inch K2 Granite The best available information indicates

The best available information indicates that the stone is a type of Dolomite that has been altered by volcanic activity

is a calcium aluminium hydroxy sorosilicate belonging to the epidote group of minerals

Herkimer County

Terahertz is a spectacular man made ore

Iolite 10mm Round A Grade - 15-16 Inch K2 Granite The best available information indicatesIolite 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.