Smoky Quartz
Quartz var. Smoky Quartz (Beta-Quartz) · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Trigonal; typically hexagona-prism shaped with pyramidal terminations, though this specimen is water-worn and pebbles-like.
Mineral Group
Silicates (Tectosilicates)
Chemical Formula
SiO2 (Silicon Dioxide) with Aluminum (Al) impurities and natural radiation effects
Formation Process
Igneous/Hydrothermal; formed in granitic pegmatites. The smoky color is caused by natural gamma radiation from surrounding rocks activating aluminum impurities.
About This Crystal
A small, rounded, translucent pebble with a characteristic brownish-grey 'smoky' coloration. It exhibits a vitreous luster on clean surfaces and appears internally cloudy in some regions.
Physical Characteristics
Color: Smoky brown to black; Streak: White; Cleavage: None; Fracture: Conchoidal; Specific Gravity: 2.65; Fluorescence: Generally naturally inert.
Optical Properties
Refractive Index: 1.544–1.553; Birefringence: 0.009; Optical Sign: Uniaxial (+); Pleochroism: Weak to moderate in brown hues.
Hardness & Durability
Origin Region
Brazil, Switzerland (Gury), Scotland (Cairngorm), USA (Colorado); found in granite pegmatites and metamorphic rocks.
Hardness & Durability
Mohs Hardness: 7; Toughness: Good; Stability: Very stable, though color may fade if exposed to temperatures above 200-300°C.
Care & Maintenance
Safe to clean with warm soapy water and ultrasonic cleaners. Avoid prolonged exposure to direct sunlight and extreme heat to prevent color fading.
Rarity & Value
Common; Value is generally low ($1-$10 for small pebbles), increasing with size, clarity, and specific crystal habits like Gwindels.
Special Characteristics
Dichroism visible in darker specimens; color saturation shifts from light 'tea' color to nearly opaque 'Morion' black.
Lore & History
Historically used in 12th-century China to make the first sunglasses. Culturally associated with 'grounding' energy and protection in various folklore traditions.