mineral

Milky quartz (quartz fragment)

Quartz, silicon dioxide (SiO₂)

AI-generated identification · may be incorrect

White to translucent, vitreous-to-greasy luster with irregular fracture and no obvious cleavage; Mohs hardness 7, trigonal crystal structure, and specific gravity about 2.65. The rough, granular appearance may reflect intergrown quartz grains or weathering.

Identified August 18, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich fluids crystallize in veins, cavities, and igneous or metamorphic rocks; individual specimens may range from Precambrian to recent geological ages. Commonly associated with granite, pegmatite, schist, and hydrothermal veins.

Uses & applications

Used in glass, ceramics, engineered stone, electronics, abrasives, and construction aggregate; attractive pieces are collected but this example appears common and minimally shaped.

Geological facts

Quartz is one of Earth’s most abundant minerals and is piezoelectric, producing an electrical charge when mechanically stressed.

Field identification & locations

Identify by its hardness, glassy appearance, lack of cleavage, and inability to be scratched by a steel knife; it should scratch ordinary glass. Common worldwide, especially in Brazil, Madagascar, the Alps, and many vein systems.