mineral

Milky quartz

Quartz, silicon dioxide (SiO₂)

AI-generated identification · may be incorrect

Hardness 7; white to translucent, with a vitreous-to-greasy luster. It has a hexagonal crystal structure, poor cleavage, and conchoidal fracture; the rough surface appears massive and granular.

Identified August 11, 2026More mineral →

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Physical properties

Hardness 7; white to translucent, with a vitreous-to-greasy luster. It has a hexagonal crystal structure, poor cleavage, and conchoidal fracture; the rough surface appears massive and granular.

Formation & geological history

Forms when silica-rich hydrothermal fluids or molten rock crystallize in veins and cavities, commonly in igneous and metamorphic terrains. Quartz is widespread from Precambrian rocks to the present; this specimen’s exact age cannot be determined from the image.

Uses & applications

Used in glassmaking, ceramics, abrasives, electronics, countertops, and construction aggregate; attractive pieces are collected or used decoratively. Milky quartz generally has modest commercial value.

Geological facts

Its cloudiness results from microscopic fluid inclusions, fractures, or mineral impurities rather than a different quartz composition. It may resemble calcite, but quartz is much harder and does not effervesce in dilute acid.

Field identification & locations

Common in quartz veins, granites, pegmatites, and metamorphic rocks worldwide, including Brazil, Madagascar, the United States, and the Alps. A steel file will not scratch it easily, while quartz can scratch ordinary glass; confirm with hardness and, if available, streak and acid tests.