Smoky Quartz

Description

Smoky quartz is a grey, translucent variety of quartz that ranges in clarity from almost complete transparency to an almost-opaque brownish-gray or black crystal. Like other quartz gems, it is a silicon dioxide crystal. The smoky colour results from free silicon formed from the silicon dioxide by natural irradiation. Smoky quartz is a color-variety of crystalline quartz. It ranges from a light yellowish brown to a brown that is so dark that it appears to be black. The colour of smoky quartz is produced when natural radiation, emitted from the surrounding rock, activates colour centres around aluminium impurities within the crystalline quartz.

Cairngorm is a variety of smoky quartz found in the Cairngorm Mountains of Scotland. It usually has a smoky yellow-brown colour, though some specimens are greyish-brown. Gems like this Smoky Quartz Fantasy Cut is used in Scottish jewellery and as a decoration on kilt pins and the handles of dirks. The largest known cairngorm crystal is a 23.6 kg (52 lb) specimen kept at Braemar Castle. Smoky Quartz is the National Gem of Scotland and has been considered a sacred stone there for a long time, a belief dating back to the Druids.

Quartz is common and was not historically important, but in recent times it has become a popular gemstone, especially for jewellery. Sunglasses, in the form of flat panes of smoky quartz, were used in China in the 12th century.