mineral

Milky quartz with iron-oxide staining

Quartz (silicon dioxide, SiO₂), commonly intergrown massive quartz

AI-generated identification · may be incorrect

Typically white to translucent, with a vitreous to greasy luster and irregular fracture; Mohs hardness 7, no cleavage, hexagonal crystal structure. The tan-brown surface likely reflects iron-oxide or clay staining and weathering.

Identified August 11, 2026More mineral →

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Physical properties

Formation & geological history

Quartz forms when silica-rich fluids crystallize in veins, fractures, cavities, or pegmatites, often during hydrothermal activity. Its exact geological age cannot be determined from the photograph and may range from Precambrian to recent depending on locality.

Uses & applications

Used extensively in glass, ceramics, electronics, abrasives, engineered stone, and ornamental objects; attractive translucent pieces are sold as cabinet specimens or lapidary material.

Geological facts

Milky quartz contains microscopic fluid inclusions, fractures, or mineral impurities that scatter light and create its cloudy appearance. It is one of the most abundant minerals in Earth’s continental crust.

Field identification & locations

Identify it by its glassy appearance, hardness sufficient to scratch ordinary glass, lack of cleavage, and white translucency; a steel knife should not scratch it. Common worldwide in quartz veins, granites, pegmatites, and metamorphic rocks.