mineral

Milky quartz in weathered host rock

Quartz, silicon dioxide (SiO₂), likely occurring in altered igneous or metamorphic matrix

AI-generated identification · may be incorrect

White to translucent, vitreous-to-waxy luster, massive rather than visibly crystalline; Mohs hardness 7, no cleavage, uneven fracture, specific gravity about 2.65. The brown-gray matrix appears iron-stained and weathered.

Identified August 18, 2026More mineral →

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Physical properties

Formation & geological history

Milky quartz forms when silica-rich fluids fill fractures or crystallize in veins, commonly during hydrothermal activity and metamorphism. Its exact age cannot be determined from the photograph.

Uses & applications

Common quartz is used in glass, ceramics, foundry materials, abrasives, and electronics; attractive pieces may be used as display specimens or lapidary material, though this example is not gem grade.

Geological facts

Internal microscopic fluid inclusions and defects scatter light, producing the characteristic cloudy appearance. Quartz is highly resistant to weathering and often survives as rounded stream or beach cobbles.

Field identification & locations

Identify it by its glassy white translucence, hardness, lack of cleavage, and inability to scratch it with a steel knife; quartz scratches ordinary glass. Common worldwide in quartz veins, granites, metamorphic rocks, and stream gravels.