mineral
Smoky Quartz
Silicon Dioxide (SiO2)
AI-generated identification · may be incorrectHardness: 7 (Mohs scale), Color: Brownish-grey, black, or smoky, Luster: Vitreous (glassy), Crystal System: Hexagonal/Trigonal, Specific Gravity: 2.65.
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Physical properties
Hardness: 7 (Mohs scale), Color: Brownish-grey, black, or smoky, Luster: Vitreous (glassy), Crystal System: Hexagonal/Trigonal, Specific Gravity: 2.65.
Formation & geological history
Formed in igneous and metamorphic rocks, particularly granite and pegmatites. The smoky color is created when natural radiation from surrounding rocks hits the crystal structure of clear quartz containing aluminum impurities.
Uses & applications
Used in gemstone manufacturing, jewelry (rings, pendants), decorative carving, and as a collector's mineral specimen. Historically used in the first sunglasses in 12th century China.
Geological facts
Smoky quartz is the national gemstone of Scotland, where it is often referred to as 'Cairngorm'. It can vary from translucent to nearly opaque.
Field identification & locations
Identify by its hardness (scratches glass), glass-like luster, and characteristic 'conchoidal' (shell-like) fracture. Commonly found in Brazil, Switzerland, and the United States (Colorado).
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Other mineral specimens
Gneiss or Schist
Gneiss or Mica Schist with Garnet
Metamorphic
Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Calcite–fluorite mineral specimen with iron-oxide staining
Calcite (CaCO₃), likely fluorite (CaF₂), with possible quartz and iron/manganese oxides
mineral
Epidote
Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
metamorphic
Pegmatite with Tourmaline and Quartz
Igneous Pegmatite
igneous
Septarian Pebble
Septarian nodule / Concretion
sedimentary