mineral

Smoky Quartz

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Grayish-brown to black; Luster: Vitreous (glassy); Crystal structure: Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 on Mohs scale
Color: Grayish-brown to black
Luster: Vitreous (glassy)

Identified April 14, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Grayish-brown to black; Luster: Vitreous (glassy); Crystal structure: Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Formation & geological history

Formed in igneous or metamorphic environments, specifically in pegmatites or hydrothermal veins. The color is caused by natural radiation from surrounding minerals occurring over millions of years, which affects trace aluminum impurities in the crystal lattice.

Uses & applications

Used primarily as a gemstone for jewelry, in ornamental carvings, and widely collected as mineral specimens. In industry, high-purity quartz is used in electronics and glass-making.

Geological facts

Smoky quartz is the national gem of Scotland, where it has been mined for centuries in the Cairngorm Mountains. Extremely dark, opaque specimens are often called 'Morion'.

Field identification & locations

Identify in the field by its hardness (will scratch glass), glassy luster, and 'smoky' translucency without any clear cleavage planes. Commonly found in granite-rich mountain ranges like the Alps, Himalayas, and Rockies.