Crystal Alexandrite

Chemical Formula

BeAl₂O₄

Color

Blue, Red, Green, Yellow, Pink, Purple, Gray, Multicolored

Hardness

8.5

Crystal System

Orthorhombic

Refractive Index

1.744 - 1.755

SG

3.5 - 3.8

Transparency

Transparent to nearly opaque

Double Refraction

.009

Luster

Vitreous

Cleavage

1,1 ; 3,2. Often exhibits parting along twinned crystals.

Mineral Class

Chrysoberyl