Image: <a rel="nofollow" class="external text" href="https://www.flickr.com/people/47445767@N05">James St. John</a> (CC BY 2.0)
cubiccommonSilicates
Smoky Quartz
SiO2
This specimen is a scepter quartz, featuring well-formed, transparent to translucent crystals of dark smoky quartz growing atop lighter purple amethyst.
Smoky Quartz Physical Properties
Mohs Hardness
7Crystal System
cubicLuster
vitreousStreak Color
WhiteCleavage
NoneFracture
ConchoidalSpecific Gravity
2.65Colors
brown, grey, black, purpleTransparency
Transparent to translucentType Locality
Brandberg, NamibiaMineral Group
SilicatesUses
jewelry, collector, industrialAssociated Minerals
amethyst, feldspar, micaRarity
commonGeological Context
Smoky quartz forms in igneous and metamorphic rocks, often in pegmatites or hydrothermal veins. Its characteristic color is typically caused by natural irradiation of aluminum impurities within the quartz crystal lattice.
