Achroite

This particularly rare, colorless stone is a variety of elbaite, a member of the tourmaline group. It does not show the strong dichroism characteristic of most tourmaline varieties and therefore can be cut with the table facet either parallel or perpendicular to the lenght of the crystal. Colorless tourmaline may also be produced by applying heat to light pink tourmalines.

Achroite occurs with colored tourmalines in the pegmatites of Madagascar and Pala (in California in United States),

Achroite is named after the Greek work achroos, meaning "without colour".

Achroite Properties

Chemical Composition: 
Complex borosilicate
Crystal System / Forms: 
Trigonal
Hardness: 
7.5
Specific Gravity: 
3.06
Lustre: 
Vitreous
Refractive Index / Birefringence: 
1.62-1.64 / 0.018
Sources: 
Madagascar and Pala (in California in United States)
Cuts & Uses: 
Brilliant, Mixed.