Smoky Quartz
Quartz var. Smoky Quartz (IMA-approved Crystal) · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Trigonal; Habit is typically hexagonal prisms terminated by rhombohedral faces, though this specimen is water-worn and massive/sub-angular.
Mineral Group
Silicates (Tectosilicate)
Chemical Formula
SiO2 (Silicon Dioxide) with Aluminum (Al3+) and Lithium (Li+) trace elements
Formation Process
Magmatic crystallization in pegmatites or hydrothermal deposition. The smoky color is caused by natural gamma irradiation of trivalent aluminum impurities.
About This Crystal
A translucent to nearly opaque brownish-grey quartz. This specific specimen exhibits a sub-angular, water-worn texture with a dull to vitreous luster on fresh surfaces and visible internal fractures.
Physical Characteristics
Color: Brownish-black to smoky grey; Streak: White; Cleavage: None (Indistinct); Fracture: Conchoidal; Specific Gravity: 2.65; Fluorescence: Usually inert.
Optical Properties
Refractive Index: 1.544–1.553; Birefringence: 0.009; Pleochroism: Weak to moderate in brown/tan shades; Uniaxial positive.
Hardness & Durability
Origin Region
Brazil, Madagascar, USA (Colorado/Arkansas), and the Swiss Alps; typically found in granitic pegmatites and hydrothermal veins.
Hardness & Durability
Mohs Hardness: 7; Toughness: Good (no cleavage); Stable against most chemicals except hydrofluoric acid.
Care & Maintenance
Clean with warm soapy water; safe for ultrasonic cleaning if no significant internal cavities exist. Avoid prolonged high heat which may cause color to fade or change to yellow.
Rarity & Value
Common; Value is determined by transparency and size. Natural specimens are affordable, though deeply saturated 'Morion' varieties fetch higher prices.
Special Characteristics
Natural irradiation induced color-center; common inclusions include rutile needles or fluid-filled 'negative crystals'.
Lore & History
Historically used in China for the first sunglasses in the 12th century. Metaphysically associated with grounding energy and the Root Chakra in traditional lore.