mineral

Chalcedony (Agate/Carnelian variant)

Cryptocrystalline Silica (SiO2)

Hardness: 6.5-7 (Mohs scale), Color: translucent tan to orangey-brown, Luster: waxy to vitreous, Crystal Structure: Trigonal (microscopic), Cleavage: None (conchoidal fracture)

Hardness: 6

Identified June 19, 2026More mineral →

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Physical properties

Hardness: 6.5-7 (Mohs scale), Color: translucent tan to orangey-brown, Luster: waxy to vitreous, Crystal Structure: Trigonal (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 or tumbled, likely from a river or beach environment.

Uses & applications

Used in jewelry (cabochons, beads), decorative carvings, and as a popular collector's item for rockhounding enthusiasts.

Geological facts

Chalcedony was used as early as the Bronze Age in the Mediterranean region for making cylinder seals and jewelry because of its durability and smooth texture.

Field identification & locations

Identify by its waxy luster, lack of visible crystals, and translucent nature when held to light. Commonly found in riverbeds, gravel pits, and coastal areas.

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