Since ancient times, varieties of quartz have been the most commonly used minerals in the making of jewelry and hard stone carvings. It is the 2nd most abundant mineral in the Earth’s crust. The difference in growth conditions depends on the environment (chemistry, temperature, pressure) as well as the size of the fissures and cavities it forms in. Smoky quartz is characterized as a smoky-gray, brown to black variety that gets it’s coloring due to gamma irradiation and the presence of aluminum.