An unusually large piece of dravite tourmaline from our collection of crystals, rocks and minerals. Dravite which is usually brown is rich in sodium and magnesium and if heat treated, its colour will become lighter. Although relatively common, it tends to be overlooked because it's not a bright or colourful mineral and the formations in which it occurs, can be fairly uninteresting.
This variety of tourmline was first documented in a book on mineralogy written by an Austrian professor in 1884. It was named dravite after the Drava river in Austria and Slovenia. It can be highly lustrous and boast beautiful crystallization but is rarely cut into a gemstone.
Tourmaline is the name given to a family of minerals many of which have a different composition but all have the same basic crystal structure. Dravite tourmaline is relatively hard and is graded 7 to 7½ on Mohs scale of mineral hardness.
This unusually large piece of dravite is well included with silvery mica and it's the only piece of brown tourmaline that we have in our collection. Pieces of this size are not particularly easy to find.
Tourmaline is one of the modern birthstones for the month of October with the other being opal.
Weight (grams): 205
Size (cms): 6.2 x 3.9