Smoky quartz is a variety of quartz, always black or brown in colour. The quartz stone family also includes amethyst (purple quartz), rose quartz (pink-red), citrine (yellow quartz), as well as all the various agates and jaspers.

Smoky quartz is often found in beautiful black crystals. It can be cut into beautiful brilliant gemstones and it makes an equally beautiful crystal specimen. Scientists believe the black may have been caused by natural radioactivity in the Earth.