mineral

Milky quartz with iron-oxide staining

Quartz (silicon dioxide, SiO₂)

AI-generated identification · may be incorrect

White to translucent, glassy-to-dull surface with rusty brown staining; quartz has a hardness of 7 Mohs, hexagonal crystal structure, no cleavage, and specific gravity near 2.65. The small, irregular specimen appears massive rather than well-crystallized.

Identified October 10, 2026More mineral →

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Physical properties

Formation & geological history

Likely formed when silica-rich fluids deposited quartz in a vein or fracture; iron-bearing minerals later weathered and stained its surface. Quartz veins occur in rocks of many ages, so the specimen’s age cannot be determined from the image.

Uses & applications

Quartz is used in glass, electronics, abrasives, and decorative objects; this small rough piece is mainly suitable for collecting.

Geological facts

Quartz is one of Earth’s most abundant minerals and fractures unevenly rather than breaking along cleavage planes.

Field identification & locations

Identify it by its hardness, glassy appearance, and lack of cleavage; iron staining is common on weathered quartz. It occurs worldwide in veins and many rock types; a field hardness test should be done only on an inconspicuous spot.