mineral

Smoky Quartz

Silicon Dioxide (SiO2)

Hardness: 7 on the Mohs scale; Color: translucent grey to brownish-black; Luster: vitreous (glassy); Crystal structure: hexagonal/trigonal; Cleavage: none (conchoidal fracture); Specific gravity: 2.65.

Hardness: 7 on the Mohs scale
Color: translucent grey to brownish-black
Luster: vitreous (glassy)

Identified March 9, 2026More mineral →

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Physical properties

Formation & geological history

Formed in igneous or metamorphic rocks (such as granite pegmatites or quartz veins) through natural irradiation of silicon dioxide crystals containing trace amounts of aluminum. It can range from millions to billions of years old.

Uses & applications

Commonly used in jewelry as a gemstone, for decorative ornaments, in metaphysical practices, and occasionally in glass making or electronics if high purity.

Geological facts

The dark color is due to exposure to natural radiation from surrounding rocks while the quartz is forming deep underground. Very dark, nearly black variants are known as 'Morion'. It is the national gem of Scotland.

Field identification & locations

Identify in the field by its smoky transparency and glass-like surface. It is commonly found in Brazil, Switzerland (the Alps), Madagascar, and the United States (Colorado). Collectors look for clarity and natural crystal points.