mineral

Smoky Quartz

Silicon Dioxide (SiO2)

Hardness: 7 Mohs; Color: Gray, brown, to nearly black; Luster: Vitreous; Crystal Structure: Trigonal; Cleavage: None (Conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 Mohs
Color: Gray, brown, to nearly black
Luster: Vitreous

Identified January 1, 2026More mineral →

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Physical properties

Hardness: 7 Mohs; Color: Gray, brown, to nearly black; Luster: Vitreous; Crystal Structure: Trigonal; Cleavage: None (Conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Formed in igneous and metamorphic rocks, particularly granite pegmatites and hydrothermal veins. The smoky color is caused by natural gamma irradiation of trace aluminum inclusions over millions of years.

Uses & applications

Used in gemstone jewelry, ornamental carvings, and electronics as a source of high-purity silica. It is a popular mineral specimen for collectors and metaphysical enthusiasts.

Geological facts

Deeply dark, nearly opaque smoky quartz is known as Morion. It has been used historically for sunglasses in 12th century China and as a mourning gemstone in Victorian England.

Field identification & locations

Identify in the field by its dark translucent color, lack of cleavage, and ability to scratch glass. Commonly found in mountainous regions such as the Swiss Alps, Scotland (Cairngorms), and Colorado.