mineral

Smoky Quartz

Silicon Dioxide (SiO₂)

Hardness: 7 (Mohs scale); Color: Gray to brownish-black; Luster: Vitreous; Crystal structure: Hexagonal/Trigonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65.

Hardness: 7 (Mohs scale)
Color: Gray to brownish-black
Luster: Vitreous

Identified April 4, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: Gray to brownish-black; Luster: Vitreous; Crystal structure: Hexagonal/Trigonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65.

Formation & geological history

Formed in igneous or metamorphic environments such as granite pegmatites. The smoky color results from natural irradiation of aluminum impurities within the crystal lattice over millions of years.

Uses & applications

Predominantly used as a gemstone in jewelry (rings, pendants, earrings), as well as in metaphysical collecting and decorative carvings.

Geological facts

Smoky quartz is the national gem of Scotland, where it is known as 'Cairngorm.' It was used in China as early as the 12th century to make 'sunglasses' for judges to hide their facial expressions.

Field identification & locations

Identify by its characteristic 'smoke' color and glass-like luster. It is commonly found in Brazil, Madagascar, and various locations in the United States (like Colorado and New Hampshire). Look for hexagonal prisms with pyramidal terminations.