mineral
Smoky Quartz
Silicon Dioxide (SiO2)
Hardness: 7 (Mohs), Color: Translucent grey to brownish-black, Luster: Vitreous (glassy), Crystal Structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture)
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Physical properties
Hardness: 7 (Mohs), Color: Translucent grey to brownish-black, Luster: Vitreous (glassy), Crystal Structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture)
Formation & geological history
Formed in igneous and metamorphic rocks, particularly pegmatites and hydrothermal veins, via natural irradiation of aluminum-bearing quartz over millions of years.
Uses & applications
Used in faceted gemstones, ornamental carvings, jewelry making, and as a popular metaphysical or decorative collector's specimen.
Geological facts
The smoky color is caused by natural radiation from surrounding rocks activating aluminum impurities within the crystal lattice. It is the national gem of Scotland, where it is known as Cairngorm.
Field identification & locations
Identify by its characteristic 'smoky' translucency and hexagonal crystal habit. Common in mountainous regions including the Alps, Brazil, and the United States (Colorado).
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Other mineral specimens
Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Sandstone with Mineral Veining or Crust
Sedimentary Sandstone (mostly SiO2 with Fe2O3 tinting)
sedimentary
Schist
Schist
Metamorphic
Epidote
Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
metamorphic
Gypsum (variety Selenite or Alabaster)
Calcium sulfate dihydrate (CaSO4·2H2O)
Mineral
Nephrite Jade
Nephrite
Mineral/Rock