Smoky quartz is a popular variety of quartz that ranges from light to dark brown in color due to natural irradiation. The darker varieties are often referred to as Morion. It has the same hardness as clear quartz (Mohs 7), which makes it a durable gemstone suitable for all kinds of jewelry.
The smoky color is a result of natural radiation exposure in the Earth. This irradiation involves the aluminium impurities present in the quartz and the surrounding rocks, and results in the formation of free silicon, which then aggregates into smoky brown "flaws". This is why, unlike some other gemstones, its color is not a result of impurities in the crystal. Rather, it's the result of changes to the crystal structure.
In terms of metaphysical properties, smoky quartz is considered a grounding stone that transmutes negative energies and facilitates your ability to get things done in the practical world. It enhances organizational skills and is good to have around in the workplace or home office since its properties are known to enhance communication and stimulate cooperation among your peers.
Smoky quartz is also highly protective and has a strong link with the earth and the base chakras. It is said to be beneficial in eliminating stress, anxiety, and depression, promoting calm and positive thoughts. Furthermore, it's believed to aid in detoxification on all levels and provide protection against radiation and electromagnetic smog.
Despite being one of the most common minerals on earth, fine smoky quartz crystals are valued by collectors. Notable sources of smoky quartz are Brazil, the Pikes Peak area of Colorado, USA, and the Swiss Alps, among others.