Smoky Quartz
Quartz var. Smoky Quartz (Alpha-Quartz) · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Trigonal; typically prismatic with hexagonal cross-sections, though this specimen is tumbled/massive.
Mineral Group
Silicates (Tectosilicate subgroup)
Chemical Formula
SiO2 (Silicon Dioxide) with traces of Aluminum and natural irradiation
Formation Process
Hydrothermal or Igneous (pegmatitic). Color is produced when aluminum-bearing quartz is exposed to natural gamma radiation.
About This Crystal
A translucent to nearly opaque brownish-grey quartz. This specimen is a tumbled stone with a vitreous (glassy) luster and smooth surface, showing internal veining and slight color zoning.
Physical Characteristics
Color: Smoky brown to black; Streak: White; Cleavage: None; Fracture: Conchoidal; Specific Gravity: 2.65; Fluorescence: Usually inert.
Optical Properties
Refractive Index: 1.544–1.553; Birefringence: 0.009; Pleochroism: Weak to moderate (brown/toasted-yellow); Singly refractive (uniaxial positive).
Hardness & Durability
Origin Region
Brazil, Madagascar, Switzerland (Alpine-type veins), USA (Pikes Peak, Colorado)
Hardness & Durability
Mohs Hardness: 7; Toughness: Good (no cleavage); Stable and highly wearable for all jewelry types.
Care & Maintenance
Clean with warm soapy water; safe for ultrasonic cleaners. Avoid prolonged exposure to high heat which may cause color to fade or change.
Rarity & Value
Common rarity. Value is generally low ($1-$10 for tumbled stones). Value increases for high clarity, deep uniform color, and large natural crystal points.
Special Characteristics
Subject to 'smoky' coloration via natural or artificial irradiation. Can exhibit rutilated inclusions or phantoms in some specimens.
Lore & History
Historically used in China for the first 'sunglasses' in the 12th century. Metaphysically associated with the Root Chakra and believed to be a grounding and stabilizing stone.