mineral
Smoky Quartz
Quartz (Silicon Dioxide) - SiO2
Hardness: 7 on Mohs scale. Color: Smoky gray, brownish-gray, to translucent dark gray. Luster: Vitreous (glassy). Crystal Structure: Trigonal/Hexagonal. Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.
- Hardness
- 7 on Mohs scale
- Color
- Smoky gray, brownish-gray, to translucent dark gray
- Luster
- Vitreous (glassy)
Identified More mineral →
Explore Smoky Quartz in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 7 on Mohs scale. Color: Smoky gray, brownish-gray, to translucent dark gray. Luster: Vitreous (glassy). Crystal Structure: Trigonal/Hexagonal. Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.
Formation & geological history
Formed in pegmatites, granitic rocks, and hydrothermal veins. The distinct brownish-gray color is caused by natural irradiation of aluminum impurities within the crystal lattice.
Uses & applications
Popular among gem collectors, used in jewelry, cabochons, carved ornaments, and as ornamental display minerals.
Geological facts
Smoky quartz was historically used in China during the 12th century to make early sunglasses. It is also the national gem of Scotland, where it is known as Cairngorm.
Field identification & locations
Identified by its transparent to translucent smoky gray color and vitreous fracture. Commonly found in granitic pegmatites worldwide including Brazil, Madagascar, the US (Colorado), and the Swiss Alps.
More like this
Other mineral specimens
Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Schist
Schist
Metamorphic
Sandstone with Mineral Veining or Crust
Sedimentary Sandstone (mostly SiO2 with Fe2O3 tinting)
sedimentary
Potassium Feldspar (Orthoclase)
Orthoclase (KAlSi3O8)
mineral
Gypsum (variety Selenite or Alabaster)
Calcium sulfate dihydrate (CaSO4·2H2O)
Mineral
Nephrite Jade
Nephrite
Mineral/Rock