mineral

Quartz geode (druzy quartz cavity)

Silica, SiO₂; microcrystalline-to-crystalline quartz lining a volcanic vesicle

AI-generated identification · may be incorrect

Typically Mohs hardness 7, white to pale gray, with a vitreous to sugary druzy luster and tiny quartz crystals; quartz has a trigonal crystal structure and indistinct cleavage. The rough outer rind is likely chalcedony or silica-rich volcanic rock.

Identified September 7, 2026More mineral →

Explore Quartz geode (druzy quartz cavity) 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-bearing groundwater fills gas cavities in volcanic rock, depositing chalcedony and later quartz crystals; commonly Cenozoic to Mesozoic, depending on the host deposit. The specimen appears cut or broken open to expose the cavity.

Uses & applications

Used as a decorative and educational specimen, in mineral collections, and occasionally as cabochon or ornamental material; it has little industrial value at this size.

Geological facts

The sparkling interior is called druzy quartz, produced by numerous microscopic crystal faces rather than large points. Colorless or white quartz indicates relatively few trace-element impurities.

Field identification & locations

Identify by the hollow cavity, hard glassy grains, conchoidal silica rind, and inability to scratch quartz with a steel knife; common sources include Brazil, Uruguay, Mexico, Morocco, and the United States. Exact host rock and locality cannot be confirmed from the image alone.