Gemstone profile and identification guide
Smoky Quartz
Smoky quartz is the brown variety of quartz, its colour linked to natural irradiation and trace aluminum.
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Overview
Smoky quartz is the brown variety of quartz, its colour linked to natural irradiation and trace aluminum.
Did you know? Cairngorm is a historic Scottish trade name for brown smoky quartz.
Use this profile as a collector reference and educational guide for quick on-page comparison, then validate with the interactive identification system.
Identification
Name: Smoky Quartz
Scientific classification: Silicate (Quartz)
Hardness: 7 Mohs
Transparency: transparent
Lustre: vitreous
Crystal system: Trigonal
Primary colour: Brown
Secondary colour: Grey Brown
Colour family: Browns
Shares quartz optical constants with colorless quartz; colour and zoning pattern are key field indicators.
Verification Status
Status: verified-core-fields
Reference priority: GIA, Gem-A, Mindat, International Gem Society
Core identity, locality, and physical-property fields reviewed against standard gemological references.
Values are given as practical gemological ranges where appropriate.
Physical Properties
Hardness category: hard
Hardness value: 7 Mohs
Chemical composition: Silicon dioxide (SiO2)
Crystal system: Trigonal
Common locations: Brazil, Madagascar, Switzerland (Alps), Scotland, United States
Learn more: Gem-A gemstone education resources.
Colour Variations
Transparent to translucent quartz in brown to grey-brown tones.
Optical effects: None specified in the current dataset.
Detailed Gemology
Mineral species: Quartz (smoky variety)
Mineral group: Quartz group
Chemical formula: Silicon dioxide (SiO2)
Mohs hardness: 7
Crystal system: Trigonal
Lustre: vitreous
Transparency: transparent
Streak: White
Cleavage: None
Fracture: Conchoidal
Specific gravity: 2.65
Refractive index: 1.544-1.553
Optical phenomena: None typically diagnostic
Colour range: Pale smoky grey to deep brown and near-black
Common inclusions: Veils, growth tubes, fluid inclusions, zoning
Geological environment: Pegmatites and hydrothermal veins
Principal mining regions: Brazil, Madagascar, Switzerland (Alps), Scotland, United States
Important commercial sources: Commercial smoky quartz is supplied from Brazil and Madagascar, with notable specimens from alpine and Scottish localities
Historical significance: Used in Scottish and central European jewellery traditions.
Common treatments: Irradiation and heating can be used to alter colour.
Synthetic or imitation forms: Synthetic quartz and glass simulants exist.
Common look-alikes: Brown glass, smoky topaz
Jewellery uses: Used in faceted gems, beads, carvings, and collector crystals.
Care recommendations: Generally durable; avoid strong prolonged heat and direct flame exposure that can alter colour.
Cross-check profile data with GIA Gem Encyclopedia and Mindat entry for Smoky Quartz.
Formation
Develops in quartz-bearing pegmatites and hydrothermal systems; natural radiation darkens Al-bearing quartz.
Origin
Commercial smoky quartz is supplied from Brazil and Madagascar, with notable specimens from alpine and Scottish localities
Uses
Best for: Used in faceted gems, beads, carvings, and collector crystals.
Ideal uses: Faceted jewellery and crystals that emphasize smoky body colour.
Care
Generally durable; avoid strong prolonged heat and direct flame exposure that can alter colour.
Need another candidate? Use advanced gemstone search or return to the identification guide.
Related gemstones by colour
Related gemstones by hardness
Gemstones from the same mineral family
Commonly confused gemstones
Smoky Quartz FAQ
How can I identify Smoky Quartz?
Compare hardness (7 Mohs), crystal system (Trigonal), colour profile, and lustre (vitreous) with your sample. Then cross-check related gemstones listed above.
What colour range does Smoky Quartz appear in?
Transparent to translucent quartz in brown to grey-brown tones.
Where is Smoky Quartz commonly used?
Faceted jewellery and crystals that emphasize smoky body colour.. For maintenance, follow the care guidance in this profile.
Scientific References
GIA: general gemstone identity (reviewed) - Batch 01 factual verification pass.
Gem-A: gemological terminology and testing references (reviewed) - Batch 01 factual verification pass.
Mindat: mineral species and principal localities (reviewed) - Batch 01 factual verification pass.
International Gem Society: gem trade context and treatment overview (reviewed) - Batch 01 factual verification pass.