mineral

Milky quartz (likely quartz-rich rock)

Quartz, silicon dioxide (SiO₂)

AI-generated identification · may be incorrect

White to translucent, vitreous-to-waxy luster, irregular fracture, and no obvious cleavage; Mohs hardness 7, with specific gravity about 2.65. The granular, cloudy appearance may indicate milky quartz or quartz in a weathered host rock.

Identified August 19, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich fluids crystallize in veins, cavities, and fractures, or during cooling of granitic and metamorphic rocks. Quartz is abundant throughout geologic time; the specimen’s exact age cannot be determined visually.

Uses & applications

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

Geological facts

Its cloudy appearance commonly results from microscopic fluid inclusions, fractures, or impurities. Quartz is one of Earth’s most abundant and chemically stable minerals.

Field identification & locations

Test with a steel file or quartz crystal: true quartz should resist scratching by steel, while it can scratch glass. Common worldwide in quartz veins, granite pegmatites, metamorphic rocks, and sedimentary gravels; the dark material may be iron/manganese staining or attached host rock.