Smoky is a variety of Quartz colored by trace elements built into the crystal lattice, in this case, aluminum. Irradiation of aluminum impurities within the quartz produces the grayish to brownish-black color.
Smoky Quartz facilitates connection of the root and crown chakras to bring your dreams into physical reality, the release of old stories and belief systems that no longer serve you, and helps remove radiation from the environment.