Smokey Quartz

History
Brown or smoky quartz, while a relative newcomer to the gemstone scene, has been popular in Scotland for hundreds of years. Known as cairngorm, and named after the Scottish region it was first discovered, this variety of smoky quartz was prized by the clans and fashioned into gems which were worn on kilts and the hilts of daggers and swords.

Features
Smoky quartz is generally pale grey brown to dark brown or black. It is frequently flawless, though it may also occur with golden rutile needles inside, and occasionally with black tourmaline needles within. As with most other quartzes, its crystal shape is six sided, with one end terminating in a point, while the other end is broken.

Treatments
Smoky quartz occurs naturally, however amethyst, chrysoprase (green quartz) and rock crystal (colorless quartz) can be either heat treated or irradiated to produce smoky quartz as well.

Principal Deposits
Scotland is the only known location for cairngorm. Smoky quartz can also be found in Brazil, Spain, Australia and the US.

Rarity 
Naturally occurring smoky quartz is somewhat rare, with a large percentage of commercially available product being the result of treatment with heat and or irradiation.