mineral

Smoky Quartz

Smoky Quartz (SiO2: Silicon Dioxide)

Hardness: 7 on Mohs scale; Color: Range from light translucent grey to brownish-black; Luster: Vitreous; Crystal structure: Trigonal/Hexagonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Range from light translucent grey to brownish-black
Luster: Vitreous

Identified March 25, 2026More mineral →

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Physical properties

Formation & geological history

Formed in igneous or metamorphic rocks (especially pegmatites). The color is produced by natural irradiation of aluminum-containing rock-forming minerals, creating color centers within the crystal lattice.

Uses & applications

Used primarily in jewelry (faceting and cabochons), metaphysical crystal healing, and industrial applications for its piezoelectric properties. High-clarity specimens are prized by collectors.

Geological facts

Darker, almost opaque black varieties are known as 'Morion'. It is the national gemstone of Scotland, where it is often referred to as 'Cairngorm' quartz.

Field identification & locations

Identify in the field by its hardness (will scratch glass), terminal points on crystals, and translucent brown tone. Common locations include Brazil, Switzerland, Madagascar, and the USA (Colorado).