gemstone

Smoky Quartz (Faceted)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Grayish-yellow to deep brownish-black; Luster: Vitreous; Crystal Structure: Trigonal/Hexagonal; Cleavage: None/Conchoidal fracture; Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Grayish-yellow to deep brownish-black
Luster: Vitreous

Identified July 20, 2026More gemstone →

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Physical properties

Hardness: 7 on Mohs scale; Color: Grayish-yellow to deep brownish-black; Luster: Vitreous; Crystal Structure: Trigonal/Hexagonal; Cleavage: None/Conchoidal fracture; Specific Gravity: 2.65

Formation & geological history

Formed in igneous or metamorphic environments, primarily in pegmatites and hydrothermal veins. The smoky color is caused by natural irradiation of aluminum-bearing quartz over millions of years.

Uses & applications

Primarily used in jewelry (faceting, beads, and carvings) and as a decorative collector's specimen. Its durability makes it suitable for rings and pendants.

Geological facts

Smoky quartz is the national gem of Scotland, where it is often called 'Cairngorm' after the Cairngorm Mountains. Historically, the first sunglasses were made from flat panes of smoky quartz in 12th-century China.

Field identification & locations

Identify by its transparency and characteristic semi-translucent smoky hue. Common locations include Brazil, Switzerland, Madagascar, and the USA (Colorado). Unlike obsidian, it is harder and maintains a crystalline structure.