About Cats Eye

A variety of chrysoberyl with acicular mineral inclusions oriented in relation to the vertical axis of the chrysoberyl crystal structure capable of producing chatoyancy is identified as cymophane.

In its structure these innumerable microscopic needle like inclusions create a silky reflection effect. The solid mineral inclusions some times may not be present but the hollows or tubes that once contained these could produce the same effect.

Mineral Blue Sapphire
Chemistry BeAl2O4
Refractive Index 1.745  to 1.754
Specific Gravity  3.5–3.84
Mohs Hardness 8.5