mineral

Milky quartz fragment

Quartz (silicon dioxide, SiO₂), likely massive or vein quartz

AI-generated identification · may be incorrect

White to translucent gray, vitreous-to-dull luster, granular fracture, and no obvious cleavage; Mohs hardness 7, specific gravity about 2.65. The tan coating may be iron-oxide staining or adhering soil.

Identified September 5, 2026More mineral →

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Physical properties

Formation & geological history

Likely formed in a hydrothermal quartz vein or pegmatitic cavity as silica-rich fluids cooled, commonly during Precambrian to younger igneous or metamorphic events. Exact age and locality cannot be determined from the photograph.

Uses & applications

Used extensively as an industrial silica source, in glass and ceramics, abrasives, engineered stone, and electronics; attractive transparent pieces may be cut or collected. This small rough specimen has minimal commercial value.

Geological facts

Quartz is one of Earth’s most abundant minerals and is the defining component of many quartz veins and sandstones. Milky appearance results from microscopic fluid inclusions, fractures, or impurities scattering light.

Field identification & locations

Identify by its hardness— it can scratch ordinary glass—lack of cleavage, and six-sided crystal habit when crystals are present; quartz veins are common worldwide, including Brazil, the United States, Madagascar, and the Alps. The pictured piece could also be quartz-bearing rock rather than pure quartz.