mineral

Smoky Quartz

Silicon Dioxide (SiO2) with aluminum impurities

Hardness: 7 on Mohs scale; Color: Translucent grey to brown/black; Luster: Vitreous; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 on Mohs scale
Color: Translucent grey to brown/black
Luster: Vitreous

Identified April 6, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Translucent grey to brown/black; Luster: Vitreous; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Formation & geological history

Formed in igneous rocks like granite or pegmatites when natural radiation from surrounding rocks affects aluminum impurities within the quartz structure over millions of years.

Uses & applications

Commonly used in jewelry (faceting and beads), as ornamental display pieces, and in metaphysical gemstone collections.

Geological facts

The dark color is caused by the exposure of standard quartz to natural gamma radiation which activates aluminum ions in the crystal lattice. If heated to high temperatures, it can lose its smoky color.

Field identification & locations

Identify in the field by its distinct translucent 'smoke' color, high hardness (will scratch glass), and lack of cleavage planes. Found globally in granitic mountain ranges.

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