A Geoscience Digital Image Library

TitleSmoky quartz
DescriptionSmoky quartz, SiO2 (silicon dioxide), is a popular variety of quartz. It has an unusual color for a gemstone. The color of smoky quartz is variable from brown to black. The cause of the color of smoky quartz is in question, but it is almost certainly related to the amount of exposure to radiation that the stone has undergone. Natural smoky quartz often occurres in granitic rocks which have a small, but persistant amount of radioactivity.
LocationBrazil. Near Minas Gerais.
PhotographerDarla Sondrol. 2002-03-22.
CollectionWard’s Classroom Collection of Gem Minerals #17.
Key wordsquartz, smoky, Brazil
Tech details379 KB. Hand specimen. Fujifilm FinePix S1Pro digital camera; 60mm AF Nikon micro lens.
GeoDIL number2518