mineral

Milky quartz (likely quartz-rich specimen)

Quartz, silicon dioxide (SiO₂)

AI-generated identification · may be incorrect

White to translucent, vitreous-to-pearly luster with irregular granular or crystalline texture; Mohs hardness 7, no cleavage, conchoidal fracture, trigonal crystal structure, specific gravity about 2.65. The image is insufficient to confirm crystal habit or exclude calcite, gypsum, or a coated material.

Identified September 8, 2026More mineral →

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Physical properties

Formation & geological history

Quartz commonly crystallizes from silica-rich hydrothermal fluids, cavities in igneous rocks, or metamorphic veins; specimens may range from ancient Precambrian to geologically recent. Milky appearance results from microscopic fluid inclusions or fractures.

Uses & applications

Used in glass, ceramics, electronics, abrasives, engineered stone, and as a low-value lapidary material; attractive clear varieties are gemstones.

Geological facts

Quartz does not scratch easily with a steel knife, though it can scratch ordinary glass. A vinegar or dilute acid test can help distinguish calcite: calcite effervesces, quartz does not.

Field identification & locations

Common worldwide in hydrothermal veins, pegmatites, and quartz-rich metamorphic rocks; major sources include Brazil, Madagascar, the United States, and Arkansas. Field identification requires hardness testing and, ideally, a streak and acid comparison.