sedimentary

Chalcedony (Tumbled Agate/Jasper)

Silicon dioxide (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs scale); Color: Tan, beige, translucent white; Luster: Waxy to vitreous; Structure: Microcrystalline quartz; Cleavage: None; Specific Gravity: 2.6

Hardness: 6
Color: Tan, beige, translucent white
Luster: Waxy to vitreous

Identified July 17, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 (Mohs scale); Color: Tan, beige, translucent white; Luster: Waxy to vitreous; Structure: Microcrystalline quartz; Cleavage: None; Specific Gravity: 2.6

Formation & geological history

Formed from the deposition of silica-rich groundwater in cavities of igneous or sedimentary rocks. This specimen is a water-worn or tumbled river pebble.

Uses & applications

Commonly used in jewelry, lapidary art, and as decorative pocket stones or vase fillers.

Geological facts

Chalcedony is the general term for all microcrystalline quartz varieties. Agate and Jasper are specialized forms of Chalcedony defined by their patterns and transparency.

Field identification & locations

Identified by its waxy luster, conchoidal fracture (visible in the small pit), and inability to be scratched by a steel knife. Commonly found in riverbeds and coastal regions.