mineral

Milky quartz (rough quartz crystal)

Quartz, silicon dioxide (SiO₂)

AI-generated identification · may be incorrect

Typically Mohs hardness 7, vitreous to waxy luster, translucent white to cloudy color, and no true cleavage; it has conchoidal fracture and a trigonal crystal structure. The specimen appears as a rough, irregular, partly crystalline piece with cloudy inclusions or internal fractures.

Identified September 16, 2026More mineral →

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Physical properties

Formation & geological history

Quartz crystallizes from silica-rich hydrothermal fluids, pegmatites, and igneous or metamorphic rocks; milky opacity usually results from microscopic fluid inclusions and fractures. Its exact geological age and locality cannot be determined from the photograph.

Uses & applications

Common quartz is used in glass, ceramics, abrasives, engineered stone, and electronics; attractive crystals are collected or used decoratively, though this piece appears low-grade for jewelry.

Geological facts

Quartz is one of Earth’s most abundant minerals and is the defining component of many quartz veins and sandstones. It can produce a piezoelectric signal when mechanically stressed.

Field identification & locations

Identify it by its glassy appearance, hardness sufficient to scratch ordinary glass, lack of cleavage, and conchoidal fracture; calcite or glass may resemble it but are softer or behave differently. Common sources include Brazil, Madagascar, the United States, and worldwide quartz-bearing veins.