Characteristics of Andalusite:

Chemical Name: Aluminum silicate

Formula: Al₂(SiO₄)O

Colors: Pink, brown, white, grey, violet, yellow, green, blue

Structure: Orthorhombic

Hardness: 7.5

Specific Gravity: 3-3.2

Refractive Index: 1.63-1.64

Lustre: Vitreous

Streak: White

Locations: Belgium, Australia, Russia, Germany, USA

What is Andalusite? 

Crystals of Andalusite are pleochroic, meaning they appear to be different colors when viewed from different angles. Andalusite is named after Andalusia, the Spanish region where it was first discovered. It is an aluminum silicate, closely related to both sillimanite and kyanite, with which it shares the same chemical composition, but it has a different crystal structure. A strikingly beautiful but relatively lesser-known gem type, Andalusite is most often opaque or translucent, with transparent specimens being extremely rare.