Dravite

Dravite is a very dark colored (usually brown) form of tourmaline, rich in magnesium. It is possible to lighten the color by heat treatment. Dravite shows strong dichroism, and should therefore be cut with the table facet parallel to the length of the crystal in order to show a lighter and more attractive color.

Dravite can occur as single crystals, or as parallel or radiating groups. Brown tourmaline and yellow tourmaline occur together in the gem gravels of Sri Lanka. It is also found in the United States, Canada, Mexico, Brazil and Australia.

The name "dravite" is derived from the district of Drave, in Austria.

Dravite Properties

Chemical Composition: 
Complex borosilicate
Crystal System / Forms: 
Trigonal
Hardness: 
7.5
Specific Gravity: 
3.06
Lustre: 
Vitreous
Refractive Index / Birefringence: 
1.61-1.63 / 0.018
Sources: 
Sri Lanka, United States, Canada, Mexico, Brazil and Australia.
Cuts & Uses: 
Brilliant, Mixed, Cushion.