mineral

Smoky Quartz

Silicon Dioxide (SiO2)

AI-generated identification · may be incorrect

Mohs hardness: 7. Color: translucent brown to gray-black. Luster: vitreous. Crystal structure: hexagonal/trigonal. No cleavage; conchoidal fracture. Specific gravity: 2.65.

Hardness: 7
Color: translucent brown to gray-black
Luster: vitreous

Identified July 7, 2026More mineral →

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Physical properties

Mohs hardness: 7. Color: translucent brown to gray-black. Luster: vitreous. Crystal structure: hexagonal/trigonal. No cleavage; conchoidal fracture. Specific gravity: 2.65.

Formation & geological history

Forms in igneous and metamorphic rocks, particularly granites and pegmatites. The smoky color is produced by natural gamma irradiation of trace aluminum impurities within the crystal lattice over millions of years.

Uses & applications

Widely used for ornamental jewelry, metaphysical collecting, and as a source of silicon for electronics in lower-grade forms.

Geological facts

The smoky color can be deeped or altered by artificial irradiation or heat treatment. It was famously used to make the first 'sunglasses' in 12th century China to block the glare from the sun.

Field identification & locations

Identify in the field by its distinct smoky transparency, hardness (scratches glass), andLack of cleavage. Commonly found in Brazil, Madagascar, and the Swiss Alps.