mineral

Rough smoky quartz crystal

Quartz (SiO₂), smoky variety

AI-generated identification · may be incorrect

Mohs hardness 7; translucent brown to smoky gray with a vitreous luster and hexagonal crystal structure. The specimen appears to have irregular, partly broken crystal faces; quartz has no true cleavage and shows conchoidal fracture.

Identified October 10, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich fluids crystallize in cavities and veins, commonly in granites and pegmatites. Its smoky color results from natural irradiation acting on trace aluminum; the image alone cannot establish its geological age.

Uses & applications

Used as a gemstone, ornamental stone, and collector specimen; quartz is also widely used in glass, abrasives, and electronics.

Geological facts

Smoky quartz’s color can range from pale gray to nearly black, and heating may lighten or alter it.

Field identification & locations

Identify by its glassy luster, hardness, lack of cleavage, and typically six-sided crystal form. Common sources include Brazil, the Alps, Madagascar, and the United States; the pictured piece looks like a rough crystal fragment.