mineral

Milky quartz

Quartz (silicon dioxide, SiO₂)

AI-generated identification · may be incorrect

Hardness 7 Mohs; white to translucent, vitreous-to-waxy luster, and irregular conchoidal fracture. It lacks prominent cleavage and consists of interlocking trigonal quartz crystals, though crystal faces are not visible here.

Identified August 24, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich fluids crystallize in veins, cavities, and pegmatites, or as a component of igneous and metamorphic rocks. Quartz is common throughout Earth’s geologic history; this specimen’s exact age cannot be determined from the image.

Uses & applications

Used for glass, ceramics, abrasives, engineered stone, and electronics; attractive pieces are sold as inexpensive mineral specimens. It is occasionally used in cabochons and carvings.

Geological facts

The cloudy appearance results from microscopic fluid inclusions, fractures, or mineral impurities. Quartz is one of the most abundant minerals in Earth’s continental crust.

Field identification & locations

Common worldwide, including Brazil, Madagascar, the United States, and alpine regions. Field tests include scratching glass but not being scratched by a steel knife; verify that it is not calcite, which is much softer and cleaves readily.