mineral

Milky quartz (rough quartz crystal)

Quartz, silicon dioxide (SiO₂)

AI-generated identification · may be incorrect

Hardness 7 Mohs; translucent white to pale gray/tan, vitreous to waxy luster, hexagonal crystal structure, and no true cleavage with conchoidal fracture. The irregular rounded form appears naturally weathered or broken.

Identified August 8, 2026More mineral →

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Physical properties

Formation & geological history

Forms in igneous and metamorphic rocks, especially hydrothermal veins and pegmatites, through silica-rich fluids; quartz commonly ranges from Precambrian to recent geological ages. The brown surface may be iron staining or attached host material.

Uses & applications

Used for glass, ceramics, electronics, abrasives, and engineered stone; attractive translucent pieces are collected or used decoratively. This small rough specimen has modest commercial value.

Geological facts

Quartz is one of Earth’s most abundant minerals and is piezoelectric, producing an electrical charge when mechanically stressed.

Field identification & locations

Identify by its glassy appearance, conchoidal fracture, lack of cleavage, and ability to scratch ordinary glass; it should not be confused with softer calcite. Common worldwide, including Brazil, Madagascar, the Alps, and U.S. hydrothermal districts.