Smoky Quartz
The brown to black variety of quartz, colored by natural irradiation of aluminum impurities.
Physical & Optical Properties
RI Range1.544–1.553
SG Range2.63–2.65
SG Typical2.65
Hardness (Mohs)7
Crystal SystemTrigonal
Optic CharacterDR Uniaxial (+)
Birefringence0.009
Dispersion0.013
Fluorescence LWInert
Fluorescence SWInert
Chelsea FilterInert
PleochroismWeak
ColorsBrown, Black
SpeciesQuartz
Related: Quartz Varieties
Key Differentiators
- 'Bull's eye' optic figure
- Color caused by natural irradiation
- RI and SG specific to quartz
Treatments
- Irradiation (to create or deepen color)
Price Context
Natural — low ($/ct)$2
Natural — high ($/ct)$10
NotePer carat; dark brown to black (Morion variety); large clean stones are common
Price context is approximate. GemID is not an appraisal tool. Results are indicators, not certified valuations.
About Smoky Quartz
The brown to black variety of quartz, colored by natural irradiation of aluminum impurities.
Identifying a smoky quartz? GemID walks through these tests in order — RI, SG, fluorescence, and more.
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