mineral

Quartz (Smoky Quartz variant)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Grayish-brown to translucent; Luster: Vitreous (glassy); Crystal Structure: Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

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

Identified May 6, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Grayish-brown to translucent; Luster: Vitreous (glassy); Crystal Structure: Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Forms in igneous rocks like granite or metamorphic rocks. The smoky color is caused by natural irradiation of aluminum-containing quartz during its formation in the earth's crust over millions of years.

Uses & applications

Used in jewelry as gemstones, in electronics for its piezoelectric properties, and in making glass and silicon for solar panels.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Its smoky color is often deep and uniform in natural specimens, though some can be synthetically enhanced.

Field identification & locations

Identify by its hardness (it will scratch glass), its lack of cleavage, and its characteristic greasy to vitreous luster. Commonly found in mountainous regions or riverbeds.