Smoky Quartz
Quartz var. Smoky Quartz · Semi-Precious Gemstone and Mineral Specimen
Crystal System
Trigonal, typically forming prismatic crystals, massive chunks, or crystalline clusters
Mineral Group
Silicates, specifically Tectosilicates
Chemical Formula
SiO2
Formation Process
Forms primarily through hydrothermal processes and igneous pegmatitic activity where natural irradiation from surrounding radioactive rocks alters the silicon dioxide lattice
About This Crystal
A translucent to transparent crystalline specimen exhibiting a characteristic brownish-gray to deep brown smoky coloration, vitreous luster, and an irregular, fractured surface showing internal light scattering
Physical Characteristics
Color ranges from light brownish-gray to deep blackish-brown; white streak; no cleavage; conchoidal fracture; specific gravity of approximately 2.65; brittle tenacity; exhibits strong piezoelectric properties
Optical Properties
Uniaxial positive with a refractive index of 1.544 to 1.553, low birefringence of 0.009, and weak dichroism
Hardness & Durability
Origin Region
Found globally with notable deposits in Brazil, Madagascar, the United States (Colorado), and the Swiss Alps, typically in pegmatites and hydrothermal veins
Hardness & Durability
Mohs hardness of 7, making it durable for daily wear in jewelry with good toughness though vulnerable to thermal shock
Care & Maintenance
Clean with warm soapy water using a soft brush; avoid harsh chemicals, ultrasonic cleaners, and prolonged direct sunlight which may cause the color to lighten
Rarity & Value
Common and widely accessible, with value determined by clarity, depth of color saturation, and size, typically ranging from inexpensive tumbling rough to moderately priced cut gems
Special Characteristics
Natural coloration caused by trace aluminum impurities activated by natural or artificial gamma irradiation, sometimes featuring internal fractures that create sparkling light reflections
Lore & History
Historically used by ancient Scottish and Celtic cultures for ornamentation and weaponry, and traditionally associated in metaphysical practices with grounding, protection, and the root chakra