Smoky Quartz
Quartz var. Smoky Quartz (IMA-approved: Quartz) · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Trigonal system; commonly occurs as hexagonal prisms with pyramidal terminations or in massive/water-worn forms as shown.
Mineral Group
Silicates (Tectosilicate subgroup)
Chemical Formula
SiO2 (Silicon Dioxide with trace aluminum impurities and natural irradiation)
Formation Process
Magmatic or hydrothermal. Forms at temperatures between 400-600°C. The brown color is created when natural radiation within the earth alters trace aluminum in the quartz lattice.
About This Crystal
A translucent to nearly opaque brownish-black specimen. This specific piece appears as a water-worn or tumbled cobble with a vitreous to greasy luster, exhibiting internal cracks and a dark, moody coloration typical of 'Morion' quartz.
Physical Characteristics
Color: Brown to black; Streak: White; Cleavage: None (poor); Fracture: Conchoidal; Specific Gravity: 2.65; Fluorescence: Generally inert under UV light.
Optical Properties
Refractive Index: 1.544–1.553; Birefringence: 0.009 (uniaxial positive); Pleochroism: Weak to moderate brown tones; Singly refractive.
Hardness & Durability
Origin Region
Brazil, Switzerland (Alps), USA (Colorado/Arkansas), Scotland, and Madagascar; typically found in granitic pegmatites and hydrothermal veins.
Hardness & Durability
Mohs Hardness: 7; Toughness: Good (no cleavage); Highly durable and suitable for all jewelry types; stable against most chemicals except hydrofluoric acid.
Care & Maintenance
Clean with warm soapy water and a soft brush. Avoid ultrasonic cleaners if there are many internal fractures. Store away from intense sunlight as some varieties may fade over long periods.
Rarity & Value
Common; Value is determined by clarity and size. Darker, eye-clean specimens are most prized. Generally affordable, ranging from $1 to $10 per carat for cut stones, much lower for rough/tumbled material.
Special Characteristics
May contain 'phantom' growth layers or rutile inclusions. Darkest specimens are known as Morion. Exhibits piezoelectricity under mechanical stress.
Lore & History
Historically used in Scotland (Cairngorm stone) for weapon hilts and jewelry. Traditionally associated with the Root Chakra in crystal healing, believed to aid in grounding and neutralizing negative energy.