mineral

Milky quartz (likely quartz pebble)

Quartz, silicon dioxide (SiO₂)

AI-generated identification · may be incorrect

Hardness 7 Mohs; white to translucent, vitreous-to-waxy luster, massive rather than visibly crystalline, and no true cleavage (conchoidal fracture). Specific gravity is about 2.65.

Identified September 13, 2026More mineral →

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Physical properties

Hardness 7 Mohs; white to translucent, vitreous-to-waxy luster, massive rather than visibly crystalline, and no true cleavage (conchoidal fracture). Specific gravity is about 2.65.

Formation & geological history

Forms when silica-rich fluids crystallize in veins, cavities, or pegmatites; its cloudy appearance comes from microscopic fluid inclusions or fractures. Quartz ranges from Precambrian to modern geological ages and occurs worldwide.

Uses & applications

Used for glass, ceramics, abrasives, foundry materials, electronics, and ornamental objects; attractive pieces may be sold as specimens or cabochons.

Geological facts

The image appears to show a polished or naturally water-worn piece, but the rounded shape and surface treatment obscure diagnostic features. It could also be another white mineral, such as calcite, if it fails a hardness test.

Field identification & locations

Look for glass-scratching hardness and conchoidal fracture; quartz will not fizz in dilute hydrochloric acid, whereas calcite fizzes and is much softer. Common sources include Brazil, Madagascar, the Alps, and many local quartz veins.