Smoky Quartz With Microcline Feldspar

A lovely Smoky quartz specimen from the Wild Blue Indian Claim near Lake George Colorado. Smoky quartz is a black to rootbeer colored variety of quartz. It gets its color from what is known as a "color center". Color centers are atomic level structural damage caused by radiation trapping impurities outside of their normal positioning in a crystalline structure. This affects how light is absorbed by the crystal and we then see, well, color! In the case of Smoky quartz the impurity is aluminum. Interestingly amethyst gets its color the same way, but from iron inclusions. 

Note: Black quartz is not the same as Smoky quartz. It has to get color from a color center to be considered Smoky quartz.