mineral

Milky quartz (rough crystal)

Quartz, silicon dioxide (SiO₂)

AI-generated identification · may be incorrect

Typically hardness 7 Mohs, white to translucent, with a glassy luster and hexagonal crystal structure. It has no true cleavage, but commonly shows conchoidal fracture; the photograph’s blur limits certainty, and the apparent flat faces may also reflect cleavage-like growth surfaces.

Identified August 12, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich fluids crystallize in veins, cavities, and pegmatites, commonly in igneous and metamorphic rocks. Quartz is extremely widespread and occurs from ancient Precambrian terrains to modern hydrothermal deposits.

Uses & applications

Used extensively in glass, ceramics, foundry sand, electronics, abrasives, and engineered stone; attractive transparent or well-formed pieces are collected, though milky quartz usually has modest value.

Geological facts

The cloudy appearance is caused by microscopic fluid inclusions, fractures, or other internal defects. Quartz is one of Earth’s most abundant minerals and is the defining mineral of many quartz veins.

Field identification & locations

Look for a hard, pale translucent material that scratches ordinary glass and leaves no streak on an unglazed tile; it should not fizz in dilute acid. Common localities include Brazil, Madagascar, the United States, and worldwide quartz-vein regions.