mineral

Quartz (Smoky Quartz variant)

Silicon Dioxide (SiO2)

Hardness: 7 on the Mohs scale; Color: Grayish-brown to smoke-colored; Luster: Vitreous (glassy); Crystal structure: Hexagonal (trigonal); Cleavage: Indistinct; Specific Gravity: 2.65

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

Identified July 5, 2026More mineral →

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Physical properties

Hardness: 7 on the Mohs scale; Color: Grayish-brown to smoke-colored; Luster: Vitreous (glassy); Crystal structure: Hexagonal (trigonal); Cleavage: Indistinct; Specific Gravity: 2.65

Formation & geological history

Forms in many geological environments but primarily in igneous rocks like granite and in metamorphic rocks. Smoky color results from natural irradiation of aluminum-bearing quartz over geological time.

Uses & applications

Used in glassmaking, electronics (piezoelectric crystals), high-precision watches, jewelry, and for metaphysical purposes.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Its smoky variety is the national gem of Scotland, where it is known as 'Cairngorm'.

Field identification & locations

Identify in the field by its hardness (will scratch glass), lack of cleavage (conchoidal fracture), and greasy/vitreous luster. Found worldwide, especially in mountain ranges.