mineral

Milky quartz with iron-oxide staining

Quartz, silicon dioxide (SiO₂), with limonite/goethite staining

AI-generated identification · may be incorrect

Hardness 7 Mohs; white to translucent, vitreous to waxy luster, conchoidal fracture, no cleavage, and a hexagonal crystal structure. The yellow-orange coloration is likely surface or vein iron-oxide staining.

Identified September 12, 2026More mineral →

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Physical properties

Formation & geological history

Quartz precipitates from silica-rich hydrothermal fluids or crystallizes in igneous and metamorphic veins; iron oxides later stain fractures and surfaces. Its exact geological age cannot be determined from the photograph.

Uses & applications

Common quartz is used in glass, ceramics, abrasives, and electronics; attractive pieces are sold as inexpensive mineral specimens or lapidary material.

Geological facts

Quartz scratches ordinary steel or glass, although weathered surfaces may feel softer. Milky appearance results from microscopic fluid inclusions and structural defects.

Field identification & locations

Common worldwide in quartz veins, granite pegmatites, metamorphic rocks, and gravel deposits; test an inconspicuous edge with a steel file or glass, while noting that staining can obscure the test.