mineral

Smoky Quartz

Silicon Dioxide (SiO2) with aluminum impurities and natural irradiation

Hardness: 7 on Mohs scale; Color: ranges from pale smoky grey to deep translucent brown/black; Luster: vitreous (glass-like); Crystal structure: trigonal (hexagonal prisms); Cleavage: none, conchoidal fracture; Specific gravity: 2.65.

Hardness: 7 on Mohs scale
Color: ranges from pale smoky grey to deep translucent brown/black
Luster: vitreous (glass-like)

Identified June 23, 2026More mineral →

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Physical properties

Formation & geological history

Smoky quartz typically forms in igneous rocks like pegmatites or in hydrothermal veins. The smoky color is caused by natural gamma radiation from the surrounding rock that activates aluminum impurities within the crystal lattice. This process can happen over millions of years.

Uses & applications

Used extensively in gemstone jewelry, ornamental carvings, and as a popular mineral specimen for collectors. Historically used for one of the first types of sunglasses in China during the 12th century.

Geological facts

Darker, nearly opaque black varieties are known as 'Morion.' It is the national gem of Scotland, where it is often referred to as 'Cairngorm' after the mountain range where it is found.

Field identification & locations

Identify by its characteristic 'smoky' translucence, high hardness (it will scratch glass), and lack of cleavage. Look for it in granite-rich mountain ranges or alluvial deposits where crystals have eroded from their source rock.

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Mineral/Rock

Banded Gneiss (River Rock/Pebble)

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Metamorphic Rock

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mineral