mineral

Druzy quartz in agate/geode

Quartz (SiO₂), microcrystalline chalcedony host

AI-generated identification · may be incorrect

White, sugary microcrystals with vitreous-to-sparkly luster lining cavities and thin translucent chalcedony bands. Quartz hardness is 7 Mohs, lacks cleavage, has hexagonal crystal structure, and specific gravity about 2.65; visible brown areas are likely iron-oxide staining or matrix.

Identified September 7, 2026More mineral →

Explore Druzy quartz in agate/geode 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 groundwater fills cavities in volcanic rock, depositing chalcedony and later tiny quartz crystals. Commonly Cenozoic or older, depending on the host volcanic rocks.

Uses & applications

Used as a decorative and lapidary specimen, in jewelry, cabochons, bookends, and mineral collections; generally not used structurally.

Geological facts

“Druzy” describes a coating of many minute crystals rather than a separate mineral. The sparkle comes from thousands of reflective quartz crystal faces.

Field identification & locations

Identify by its cavity-lining texture, glassy sparkle, hardness, and translucent banding; quartz will scratch glass and resist a steel knife. Common sources include Brazil, Uruguay, Mexico, Morocco, and the western United States.