mineral

Milky quartz with iron-oxide staining

Quartz, silicon dioxide (SiO₂), with hydrated iron oxides

AI-generated identification · may be incorrect

White to translucent, vitreous-to-greasy luster, massive crystalline texture, and no obvious cleavage; quartz hardness is Mohs 7, with specific gravity about 2.65. Brown-orange areas are likely limonite/goethite staining, while gray zones may be included minerals or weathering.

Identified September 2, 2026More mineral →

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Physical properties

Formation & geological history

Likely formed when silica-rich hydrothermal fluids filled fractures or cavities, later weathered and stained by oxidized iron. Quartz veins occur in rocks of many ages, from Precambrian terrains to young volcanic systems.

Uses & applications

Quartz is used in glass, ceramics, electronics, abrasives, and engineered stone; attractive pieces are sold as mineral specimens or used in cabochons. This rough specimen appears mainly collector-grade rather than gem-grade.

Geological facts

Milky quartz becomes opaque because microscopic fluid inclusions, fractures, and mineral inclusions scatter light. Iron staining commonly develops near the weathering surface of quartz veins.

Field identification & locations

Identify it by its glassy appearance, hardness, lack of cleavage, and ability to scratch ordinary glass; it should not fizz in dilute acid. Common localities include hydrothermal veins, granite pegmatites, and metamorphic belts worldwide.