Smoky Quartz
Quartz var. Smoky (Silica) · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Trigonal; typically prismatic with hexagonal cross-sections, though the pictured specimen is carved and polished into a heart shape
Mineral Group
Silicates (Tectosilicate subgroup)
Chemical Formula
SiO2 with trace amounts of Aluminum (Al) and natural irradiation
Formation Process
Magmatic or Hydrothermal; forms in pegmatites and igneous rocks through the cooling of silica-rich solutions under natural gamma radiation
About This Crystal
A translucent to transparent variety of quartz characterized by its smoky brown to blackish-grey color. The pictured heart-carved specimen shows internal fractures, veils, and cloudy inclusions with a vitreous luster.
Physical Characteristics
Color: Pale brown to black; Streak: White; Fracture: Conchoidal; Specific Gravity: 2.65; Fluorescence: Generally inert under UV light
Optical Properties
Refractive Index: 1.544–1.553; Birefringence: 0.009; Pleochroism: Weak to moderate in darker stones; Uniaxial (+)
Hardness & Durability
Origin Region
Brazil, Madagascar, USA (Colorado/New Hampshire), Switzerland, and Scotland
Hardness & Durability
7 on the Mohs scale; Excellent durability and toughness, though internal fractures make it prone to chipping if dropped
Care & Maintenance
Wash with warm soapy water; avoid prolonged exposure to intense sunlight as color may fade. Safe in ultrasonic cleaners unless heavily fractured.
Rarity & Value
Common; very affordable. Value is determined by clarity, size, and depth of color. Natural stones are inexpensive, though some are produced via irradiation of clear quartz.
Special Characteristics
Natural irradiation of aluminum impurities produces the color; may contain needle-like rutile inclusions or phantom crystal growth layers.
Lore & History
Historically used in 12th century China for the first 'sunglasses.' Symbolically associated with grounding and protection in traditional crystal lore; often linked to the Root Chakra.