Smoky Quartz
Quartz var. Smoky Quartz (IMA: Quartz) · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Trigonal crystal system; typically occurs as hexagonal prisms with pyramidal terminations; this specimen is a tumbled/polished pebble habit
Mineral Group
Silicates; Tectosilicate subgroup (Quartz group)
Chemical Formula
SiO2 with trace Al3+ ions and natural radiation-induced color centers
Formation Process
Magmatic or Hydrothermal; forms from silica-rich fluids in pegmatites or veins, where natural radiation from surrounding rock affects aluminum impurities to create the smoky color
About This Crystal
A translucent to transparent variety of quartz ranging from pale grayish-yellow to deep brownish-black ('Morion'). This specimen is translucent with a vitreous (glassy) luster and visible internal fractures and veil-like inclusions.
Physical Characteristics
Color: Smoky brown; Streak: White; Cleavage: Indistinct; Fracture: Conchoidal; Specific Gravity: 2.65; Tenacity: Brittle; Fluorescence: Generally inert under UV light
Optical Properties
Refractive Index: 1.544–1.553; Birefringence: 0.009 (uniaxial positive); Pleochroism: Weak to moderate in brown/reddish-brown tones; no dispersion or play of color visible
Hardness & Durability
Origin Region
Brazil (Minas Gerais), USA (Colorado), Switzerland, and Scotland (Cairngorm Mountains); often found in granite pegmatites and hydrothermal veins
Hardness & Durability
Mohs Hardness: 7; Excellent durability for jewelry; lacks cleavage making it resistant to chipping compared to other gemstones
Care & Maintenance
Safe to clean with warm soapy water or ultrasonic cleaners; avoid prolonged exposure to intense heat or direct sunlight as some specimens may fade; store separately to prevent scratching softer minerals
Rarity & Value
Common; value is determined by transparency and size. Large specimens are affordable. Most darker 'Cairngorm' or lighter varieties are very common; irradiation of clear quartz is a common treatment to darken color
Special Characteristics
Displays natural radiation-induced color centers; occasionally found with 'phantom' growth layers or rutile inclusions; this tumbled stone shows internal 'veils' or 'crackle' patterns
Lore & History
Historically used in China for some of the first sunglasses (12th century); culturally significant in Scotland (Cairngorm stone). Metaphysically associated with grounding, protection, and neutralizing negative energy; linked to the Root Chakra.