mineral

Smoky Quartz

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale), Color: translucent brownish-grey to smoky black, Luster: Vitreous, Crystal Structure: Trigonal/Hexagonal, Cleavage: None (Conchoidal fracture), Specific Gravity: 2.65

Identified June 27, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale), Color: translucent brownish-grey to smoky black, Luster: Vitreous, Crystal Structure: Trigonal/Hexagonal, Cleavage: None (Conchoidal fracture), Specific Gravity: 2.65

Formation & geological history

Formed in igneous and metamorphic rocks, particularly pegmatites and hydrothermal veins. The smoky color results from natural irradiation of aluminum-bearing quartz over millions of years.

Uses & applications

Commonly used in jewelry, as decorative carvings (like the butterfly shown), and in metaphysical practices. High-purity quartz is used in electronics and glass manufacturing.

Geological facts

Smoky quartz is the national gem of Scotland, where it is known as Cairngorm. Large crystals weighing hundreds of pounds have been found in the Alps and Brazil.

Field identification & locations

Identify by its characteristic smoky transparency and lack of cleavage. Found globally, with major deposits in Brazil, Madagascar, and the Swiss Alps. For collectors, look for internal fractures or inclusions called 'veils'.