Smoky Quartz
Quartz var. Smoky Quartz (Beta-Quartz) · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Trigonal (Hexagonal system); typically prismatic habit with pyramidal terminations, often found in massive or microcrystalline clusters.
Mineral Group
Silicates (Tectosilicate subgroup / Quartz group)
Chemical Formula
SiO2 (Silicon Dioxide) with natural irradiation of trace Aluminum (Al) impurities.
Formation Process
Igneous/Hydrothermal: Forms as magma cools or through mineral-rich hydrothermal fluids. The brown/black color is caused by natural gamma radiation from surrounding rocks acting on trace aluminum within the crystal lattice.
About This Crystal
Small, granular to massive specimen with a dark grey-brown to black coloration. It shows a vitreous to greasy luster on fresh surfaces, varying from translucent to nearly opaque (Morion).
Physical Characteristics
Color: Smoky grey-brown to black; Streak: White; Cleavage: None (Indistinct); Fracture: Conchoidal; Specific Gravity: 2.65; Fluorescence: Generally none.
Optical Properties
Refractive Index: 1.544-1.553; Birefringence: 0.009 (Uniaxial positive); Pleochroism: Weak to moderate in darker stones (brownish-yellow to brownish-black).
Hardness & Durability
Origin Region
Brazil, Switzerland (Swiss Alps), Madagascar, USA (Colorado/New Hampshire), and Australia. Common in granitic pegmatites.
Hardness & Durability
Mohs Hardness: 7; Toughness: Good; Stability: Stable but can fade if exposed to extreme heat or intense long-term UV radiation.
Care & Maintenance
Safe to clean with warm soapy water or ultrasonic cleaners. Store away from direct, prolonged sunlight to prevent color fading. Highly durable for jewelry.
Rarity & Value
Common; Value is determined by clarity and size. Gem-quality faceted stones are affordable; specimens with unique mineral inclusions (like rutile) or phantom growths are more valuable.
Special Characteristics
Color resulting from structural defects (color centers) rather than just chemical concentration; can occur as 'Morion' (opaque black) or 'Cairngorm' (yellow-brown).
Lore & History
Historically used in 12th-century China for early sunglasses. Traditionally viewed as a 'grounding' stone in crystal healing, associated with the Root Chakra and used for protection against negative energy.