Smoky Quartz
Quartz var. Smoky Quartz (IMA-approved Quartz) · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Trigonal system; habit is typically prismatic with pyramidal terminations, though this specimen is massive/crystalline
Mineral Group
Silicates (Tectosilicate subgroup)
Chemical Formula
SiO2 (Silicon Dioxide with aluminum impurities and natural irradiation)
Formation Process
Igneous/Hydrothermal: Forms in pegmatites and hydrothermal veins through late-stage cooling of silica-rich fluids
About This Crystal
A dark, translucent to opaque quartz variety with a smoky brownish-black color. The surface shows a vitreous to greasy luster with an uneven texture that suggests a raw, unpolished specimen.
Physical Characteristics
Color: Smoky brown to black; Streak: White; Cleavage: None (indistinct); Fracture: Conchoidal to uneven; Specific Gravity: 2.65; Fluorescence: Usually inert
Optical Properties
Refractive Index: 1.544–1.553; Birefringence: 0.009; Pleochroism: Weak to moderate in brown tones; Optically Uniaxial (+)
Hardness & Durability
Origin Region
Brazil, Madagascar, USA (Colorado/New Hampshire), and the Swiss Alps
Hardness & Durability
Mohs Hardness: 7; Toughness: Good; Stability: Stable, though very dark specimens may fade if exposed to extreme heat
Care & Maintenance
Clean with warm soapy water; safe for ultrasonic cleaners. Avoid prolonged high-heat exposure. Store separately from softer stones.
Rarity & Value
Common; Value is determined by clarity and size. Darker specimens known as 'Morion' are often sought after by collectors.
Special Characteristics
Color is caused by natural gamma irradiation acting on aluminum impurities within the crystal lattice.
Lore & History
Historically used in 12th-century China for sunglasses; traditionally associated with grounding, protection, and the root chakra in modern crystal healing lore.