mineral

Smoky Quartz

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale), Color: Smoky brown to black/gray, Luster: Vitreous, Crystal structure: Hexagonal (Trigonal), Cleavage: Indistinct/Conchoidal fracture, Specific gravity: 2.65

Identified March 21, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale), Color: Smoky brown to black/gray, Luster: Vitreous, Crystal structure: Hexagonal (Trigonal), Cleavage: Indistinct/Conchoidal fracture, Specific gravity: 2.65

Formation & geological history

Formed in igneous and metamorphic rocks, particularly granite pegmatites. The smoky color is caused by natural gamma radiation from the surrounding rock that activates aluminum impurities within the quartz crystal lattice.

Uses & applications

Commonly used as a gemstone in jewelry (rings, pendants, beads), for chakra healing/metaphysical collecting, and in high-quality specimens for museum or private displays.

Geological facts

Darker varieties are known as 'Morion'. It is the national gem of Scotland, where it is often referred to as 'Cairngorm' after the mountain range where it was historically found.

Field identification & locations

Identify in the field by its hardness (will scratch glass), translucent to transparent smoky color, and lack of cleavage. Common locations include Brazil, Switzerland, Madagascar, and the United States (Colorado).