Ball bracelet 10mm made of Smoky Quartz from Brazil.

Smoky quartz is a quartz variety. The color is smoke brown to almost black, translucent. Very dark varieties are called morion. Smoky quartz is most common in cavities in intrusive rocks and high-grade metamorphic rocks. Smoky quartz is rare in sedimentary rocks and effluent rocks. Locations include the Alps, Brazil, Russia, Mexico, India, Ireland, Zimbabwe, Afghanistan, and the USA. The color of smoky quartz is caused by aluminum in the crystal lattice in combination with ionizing radiation. The aluminum replaces the silicon in the crystal structure, forming the complex [AlO4-] instead of [SiO4]. To compensate for the resulting charge difference, small monovalent cations of, for example, hydrogen, lithium or sodium are simultaneously incorporated into the crystal structure during the growth of the crystal. Under the influence of ionizing radiation, the electron of the [AlO4-] complex moves to a cation, creating a color center. This process normally only occurs below 50°C. At higher temperatures, the breakdown of the color centers takes place faster than their production. The source of the ionizing radiation is usually potassium-40 in the surrounding rock. The color of smoky quartz occurs long after the crystals have formed and can take several millions of years. This is also the reason why most smoky quartz are formed in feldspar-rich rocks such as granite. When heated above 200°C, smoky quartz will lose its color. Irradiating clear quartz (rock crystal) with X-rays or gamma rays almost always produces smoky quartz. The method is therefore used to make smoky quartz from colorless quartz. In ancient times, this stone warned soldiers in battle when it turned dark. Smoky quartz is still used for rosaries and crucifixes. A number of medicinal properties are attributed to smoky quartz; it is said to help against digestive complaints, stress, sadness and help with the desire to have children. According to various literature, the mineral belongs to the zodiac sign: Libra.