SMOKEY QUARTZ
HARDNESS: 7
DENSITY: 2,65 g/cm3
SCRATCH: White
BRIGHTNESS: Vitreous, silky, matte
EXFOLIATION- FRACTURE: None - Concoidea
CRYSTALLIZATION: Trigonal system
TRANSPARENCY: Transparent to translucent, opaque
Smoky quartz is a translucent gray variety of quartz. From an almost total transparency to a brown-gray crystal that is almost opaque. Some can also be black. Like other quartz gems, it is a crystal of silicon dioxide. The smoke color is due to free silicon, which is formed from silicon dioxide by natural irradiation.