mineral

Quartz Geode (Chalcedony)

Silicon Dioxide (SiO2)

AI-generated identification · may be incorrect

Hardness: 7 on Mohs scale; Color: Creamy white to light tan; Luster: Waxy to vitreous; Crystal structure: Hexagonal (Trigonal); Cleavage: None; SG: 2.65

Hardness: 7 on Mohs scale
Color: Creamy white to light tan
Luster: Waxy to vitreous

Identified July 12, 2026More mineral →

Explore Quartz Geode (Chalcedony) in the encyclopedia →

Identify your own rocks.

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

App Store Google Play

Physical properties

Hardness: 7 on Mohs scale; Color: Creamy white to light tan; Luster: Waxy to vitreous; Crystal structure: Hexagonal (Trigonal); Cleavage: None; SG: 2.65

Formation & geological history

Formed in cavities within sedimentary or volcanic rocks by mineral-rich water precipitation. Silica-rich fluids seep into voids, slowly crystallizing over thousands of years.

Uses & applications

Primarily used as decorative display specimens, for lapidary work (slicing and polishing), and in crystal collecting.

Geological facts

This specimen shows botryoidal (grape-like) chalcedony and a central vug or cavity. Geodes are essentially time capsules of geological activity from millions of years ago.

Field identification & locations

Identify by its bumpy, nodular exterior and hollow interior. Common in limestone regions or volcanic ash beds. Look for unusually light weight for its size, indicating a hollow center.