mineral

Smoky Quartz

Quartz (Silicon Dioxide) - SiO2

Hardness: 7 on Mohs scale; Color: Grayish-brown to black; Luster: Vitreous; Crystal Structure: Hexagonal (trigonal); Cleavage: Indistinct/Conchoidal fracture; Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Grayish-brown to black
Luster: Vitreous

Identified June 21, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Grayish-brown to black; Luster: Vitreous; Crystal Structure: Hexagonal (trigonal); Cleavage: Indistinct/Conchoidal fracture; Specific Gravity: 2.65

Formation & geological history

Formed through the natural irradiation of aluminum-bearing clear quartz within granite pegmatites or hydrothermal veins. This specimen appears to have been extracted from a crystalline vein.

Uses & applications

Used in jewelry as gemstones, ornamental carvings, and widely collected by mineral enthusiasts. High-purity quartz is also used in electronics and glass manufacturing.

Geological facts

The dark color is caused by free silicon formed from the silicon dioxide by natural irradiation. If heated significantly, smoky quartz can lose its dark color and become clear or yellow.

Field identification & locations

Identify by its translucent smoky color, hexagonal crystal habits (if present), and its ability to scratch glass but not be scratched by a steel file. Commonly found in mountainous granitic regions.