mineral

Botryoidal quartz (likely milky quartz)

Quartz, silicon dioxide (SiO₂)

AI-generated identification · may be incorrect

White to translucent, glassy-to-waxy luster with rounded botryoidal crystal masses; Mohs hardness 7, no cleavage, conchoidal fracture, and specific gravity about 2.65. The granular surface and pale color are consistent with milky quartz, though calcite or chalcedony cannot be excluded from the photo alone.

Identified August 9, 2026More mineral →

Explore Botryoidal quartz (likely milky quartz) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Forms when silica-rich fluids precipitate in cavities, fractures, or vugs, commonly coating earlier minerals; its age depends on the host rock and may range from ancient to geologically recent. Botryoidal growth develops as successive rounded layers or crystal clusters form.

Uses & applications

Common quartz is used in glass, ceramics, abrasives, engineered stone, and electronics; attractive specimens are sold for mineral collecting and occasional decorative use. It is generally low-value unless exceptionally clear, large, or aesthetically distinctive.

Geological facts

Quartz is one of Earth’s most abundant minerals and is chemically resistant to weathering. A scratch test with steel or glass can help: quartz should scratch ordinary glass and resist a steel nail.

Field identification & locations

Common worldwide, including Brazil, Madagascar, the United States, and Mexico; inspect for hexagonal crystal faces, conchoidal fracture, and lack of fizz in dilute acid. Estimated value: $5–$30 for a small common specimen, potentially $50–$150 if unusually attractive.