mineral

Smoky Quartz

Silicon Dioxide (SiO2) with aluminum impurities

Hardness: 7 (Mohs); Color: translucent brown to nearly black; Luster: Vitreous; Crystal Structure: Hexagonal (Trigonal); Cleavage: Indistinct; Specific Gravity: 2.65

Hardness: 7 (Mohs)
Color: translucent brown to nearly black
Luster: Vitreous

Identified June 27, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs); Color: translucent brown to nearly black; Luster: Vitreous; Crystal Structure: Hexagonal (Trigonal); Cleavage: Indistinct; Specific Gravity: 2.65

Formation & geological history

Formed in igneous or metamorphic rocks like granite and gneiss when natural radiation from surrounding rocks activates aluminum impurities in quartz. Typically occurs in pegmatites and hydrothermal veins.

Uses & applications

Used primarily in jewelry as a gemstone, as well as in holistic practices, decorative carvings, and as a mineral specimen for collectors.

Geological facts

The dark color is caused by the exposure of trace aluminum to natural gamma radiation. In the 12th century, flat panes of smoky quartz were used in China for some of the earliest recorded 'sunglasses'.

Field identification & locations

Identify in the field by its hardness (will scratch glass), translucent brownish color, and lack of true cleavage. It is found globally, with notable deposits in Brazil, Switzerland, and the United States (notably Pikes Peak, Colorado).

Other mineral specimens

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral