Black Spinel 3mm Table Cut Cube A Grade Bead - 15-16 Inch Shape_Tube Blue Tiger Eye is a

Blue Tiger Eye is a naturally occurring dark stone with chatoyant layers that create a flash which seems to emanate from within the stone as they catch the light

Iron gives them blue

The green coloring has likened the stone of jadeite in the past

Unsealed granite may discolor when exposed to oil

Through this process

Black Spinel 3mm Table Cut Cube A Grade Bead - 15-16 Inch Shape_Tube Blue Tiger Eye is aSpinel is a hard vitreous magnesium aluminum oxide, and comes in a range of other colors, but those varieties are transparent. Black Spinel not only has the dark color, but it is opaque as well, rendering its black especially deep and mysterious. Sometimes called the "Black Prince's Ruby" for its role in the English crown. It has been mistaken for ruby and sapphire at times, but can be distinguished by its structure and its lower relative hardness.