Smoky Quartz
Quartz var. Smoky Quartz · Semi-Precious Gemstone
Crystal System
Trigonal, typically forming as prismatic crystals, massive, or tumbled/polished stones
Mineral Group
Silicates (Tectosilicates)
Chemical Formula
SiO2
Formation Process
Forms via igneous and hydrothermal processes where natural irradiation of aluminum impurities within the silica lattice creates the characteristic brown to black color
About This Crystal
A polished, translucent to transparent, elongated cabochon or tumbled stone set in a ring showing brownish-gray color zoning and internal natural inclusions
Physical Characteristics
Brown to grayish-brown color, white streak, conchoidal fracture, lack of cleavage, specific gravity around 2.65, brittle tenacity
Optical Properties
Uniaxial positive optical character, refractive index of 1.544-1.553, low birefringence, generally low pleochroism
Hardness & Durability
Origin Region
Found globally with notable sources in Brazil, Madagascar, the United States, and Switzerland; typically in pegmatites and hydrothermal veins
Hardness & Durability
Mohs hardness of 7, good durability for everyday jewelry wear although sensitive to extreme heat and prolonged direct sunlight which may fade the color
Care & Maintenance
Clean with warm soapy water and a soft brush, avoid harsh chemicals, steam cleaners, ultrasonic cleaners, and prolonged direct sunlight
Rarity & Value
Common mineral with widespread availability; affordable price range depending on clarity, cut, and size
Special Characteristics
Displays natural internal fractures, veiling, and inclusions; exhibits piezoelectric and pyroelectric properties
Lore & History
Historically used by ancient cultures including the Celts and Scots for jewelry and weaponry; associated with grounding, protection, and the root chakra in modern crystal healing practices