Smoky Quartz
Quartz (Silicon Dioxide) var. Smoky Quartz · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Trigonal; typically prismatic crystals though this specimen is water-worn and tumbled
Mineral Group
Silicates (Tectosilicate)
Chemical Formula
SiO2 (with trace amounts of Al and exposure to natural irradiation)
Formation Process
Primarily hydrothermal and magmatic crystallization; commonly found in granite pegmatites and quartz veins.
About This Crystal
A translucent to nearly opaque brownish-grey stone. This specific specimen appears to be a tumbled or river-worn pebble with a dull to vitreous luster and visible internal fractures.
Physical Characteristics
Color ranges from light grey to deep brownish-black (morion); white streak; conchoidal fracture; no cleavage; specific gravity 2.65.
Optical Properties
Refractive index of 1.544-1.553; weakly pleochroic; uniaxial positive; vitreous luster on polished surfaces.
Hardness & Durability
Origin Region
Globally distributed; notable sources include Brazil, Madagascar, Switzerland, and the United States (Colorado).
Hardness & Durability
7 on the Mohs scale; high durability; lacks cleavage making it resistant to chipping; suitable for all jewelry types.
Care & Maintenance
Generally stable. Clean with warm soapy water; avoid prolonged exposure to direct high-intensity sunlight which may fade darker varieties.
Rarity & Value
Common; value depends on clarity and depth of color. Usually affordable, though large, clear crystals command higher prices.
Special Characteristics
Color is produced by natural radiation acting on aluminum impurities within the crystal lattice.
Lore & History
Historically used in Scotland as 'Cairngorm' for jewelry. Traditionally associated with grounding, protection, and the root chakra in various cultural beliefs.