mineral

Milky quartz (rough quartz fragment)

Quartz, silicon dioxide (SiO₂)

AI-generated identification · may be incorrect

Typically white to translucent with a vitreous-to-waxy luster; Mohs hardness 7, no cleavage, conchoidal fracture, and trigonal crystal structure. The specimen appears massive and weathered, with minor iron staining or inclusions; the purple edge may indicate contact with amethyst or colored material.

Identified August 9, 2026More mineral →

Explore Milky quartz (rough quartz fragment) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Forms when silica-rich fluids crystallize in veins, cavities, and igneous or metamorphic rocks; individual quartz grains commonly range from ancient Precambrian to recent geologic ages. Common worldwide, including Brazil, Madagascar, the United States, and Arkansas.

Uses & applications

Used for glass, ceramics, abrasives, electronics, and engineered stone; attractive pieces are collected or cut for cabochons and carvings. This rough fragment has modest commercial value.

Geological facts

Quartz is one of Earth’s most abundant minerals and is piezoelectric, producing an electrical charge under pressure. Milky opacity results mainly from microscopic fluid inclusions and defects.

Field identification & locations

Identify by its glassy appearance, lack of cleavage, hardness sufficient to scratch ordinary glass, and conchoidal fracture; it should not be confused with softer calcite. Common rough specimens generally sell for about $1–$10, depending on size and appearance.