Smoky Quartz

Family: Quartz (has the same chemical composition and physical properties as amethyst) Colour; From light brown to grey brown to dark brown.
Hardness: 7 (as per Mohs hardness scale)
Sources: Smoky quartz is found in Brazil, Madagascar, the Swiss Alps, Colorado (USA), Australia, Spain and the Cairngorm Mountains in Scotland.
Interesting Facts: Smoky quartz was often carved and used in intaglio seals in Roman times.