mineral

Milky quartz

Quartz (silicon dioxide, SiO₂)

AI-generated identification · may be incorrect

White to translucent, vitreous-to-greasy luster, hardness 7 Mohs, no cleavage and conchoidal fracture; hexagonal crystal structure, though this specimen appears massive and fractured. Specific gravity is about 2.65.

Identified August 25, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich hydrothermal fluids crystallize in fractures and cavities, or during igneous and metamorphic processes. Quartz is common from Precambrian rocks to modern veins; the image may also include associated feldspar or calcite.

Uses & applications

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

Geological facts

The cloudy appearance comes from microscopic fluid inclusions, fractures, or mineral impurities. Quartz is one of Earth’s most abundant minerals and is highly resistant to weathering.

Field identification & locations

Identify it by its white translucency, glassy luster, lack of cleavage, and ability to scratch ordinary glass; a steel knife will not scratch it. Common in quartz veins worldwide, especially Brazil, the United States, Madagascar, and the Alps.