mineral

Milky quartz (rough quartz crystal)

Quartz, silicon dioxide (SiO₂)

AI-generated identification · may be incorrect

Typically Mohs hardness 7, white to translucent, with a vitreous to waxy luster and hexagonal crystal structure; quartz has no true cleavage and shows conchoidal fracture. The specimen appears massive and fractured rather than sharply crystallized, with internal cloudiness likely from microscopic fluid inclusions or fr…

Identified August 23, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich hydrothermal fluids cool in fractures and cavities, or crystallizes from igneous melts; quartz occurs from Precambrian rocks to modern veins. Exact age and locality cannot be determined from the photograph.

Uses & applications

Used in glass, ceramics, electronics, abrasives, engineered stone, and decorative objects; attractive translucent pieces are sold as inexpensive mineral specimens.

Geological facts

It can scratch ordinary steel or glass, while a steel blade will not scratch it. Milky quartz is common and is often confused with white calcite, which is softer and reacts with dilute acid.

Field identification & locations

Common in quartz veins, granite, pegmatites, metamorphic rocks, and stream gravels worldwide; test hardness and inspect for conchoidal fracture, but avoid destructive testing on valuable specimens. Likely a rough milky quartz fragment.