mineral

Chalcedony (Agate/Carnelian)

Cryptocrystalline Quartz (SiO2)

Hardness: 6.5-7 on Mohs scale; Color: Tan to honey-brown, translucent; Luster: Waxy to vitreous; Crystal Structure: Trigonal/Monoclinic (microscopic); Cleavage: None/Conchoidal fracture.

Hardness: 6
Color: Tan to honey-brown, translucent
Luster: Waxy to vitreous

Identified June 21, 2026More mineral →

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Physical properties

Hardness: 6.5-7 on Mohs scale; Color: Tan to honey-brown, translucent; Luster: Waxy to vitreous; Crystal Structure: Trigonal/Monoclinic (microscopic); Cleavage: None/Conchoidal fracture.

Formation & geological history

Formed via the deposition of silica from groundwater in cavities of igneous or sedimentary rocks. This specimen appears water-worn, likely from a river or beach environment.

Uses & applications

Used extensively in jewelry as gemstones, for lapidary carving, and historically for making hard-wearing tools like mortars and pestles.

Geological facts

Chalcedony is a broad term that includes agate, jasper, and carnelian. This specific tan/honey variety is often approaching carnelian but lacks the deep red iron oxidation.

Field identification & locations

Identify by its waxy luster, lack of visible crystals, and inability to be scratched by a steel knife. Commonly found in gravel beds or volcanic regions.

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