mineral
Smoky Quartz
Silicon Dioxide (SiO2) with aluminum impurities
Hardness: 7 on Mohs scale. Color: Translucent grey to brownish-black. Luster: Vitreous (glassy). Crystal Structure: Hexagonal (trigonal). Cleavage: None (conchoidal fracture).
- Hardness
- 7 on Mohs scale
- Color
- Translucent grey to brownish-black
- Luster
- Vitreous (glassy)
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Physical properties
Hardness: 7 on Mohs scale. Color: Translucent grey to brownish-black. Luster: Vitreous (glassy). Crystal Structure: Hexagonal (trigonal). Cleavage: None (conchoidal fracture).
Formation & geological history
Formed in igneous and metamorphic rocks, particularly pegmatites and hydrothermal veins. The color comes from natural gamma radiation that activates aluminum impurities within the quartz lattice.
Uses & applications
Commonly used in jewelry (facets and beads), metaphysical practices, and as decorative collector specimens.
Geological facts
Unlike many dark minerals, smoky quartz remains translucent even in deep shades. It is the national gem of Scotland, where it is known as Cairngorm.
Field identification & locations
Identified by its transparency and distinct smoky grey-brown color. Found globally in granitic terrains. Collectors look for clarity and well-defined crystal terminations.
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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
Potassium Feldspar (Orthoclase)
Orthoclase (KAlSi3O8)
mineral
Gypsum (variety Selenite or Alabaster)
Calcium sulfate dihydrate (CaSO4·2H2O)
Mineral
Epidote
Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
metamorphic