sedimentary

Carnelian Agate Nodule

Chalcedony (SiO2) with Iron Oxide inclusions

AI-generated identification · may be incorrect

Hardness: 6.5-7 on Mohs scale. Color: Translucent white to orange-red. Luster: Waxy to vitreous. Structure: Cryptocrystalline. Cleavage: None (conchoidal fracture).

Hardness: 6
Color: Translucent white to orange-red
Luster: Waxy to vitreous

Identified July 17, 2026More sedimentary →

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Physical properties

Hardness: 6.5-7 on Mohs scale. Color: Translucent white to orange-red. Luster: Waxy to vitreous. Structure: Cryptocrystalline. Cleavage: None (conchoidal fracture).

Formation & geological history

Formed as a secondary silica deposit in the cavities of volcanic rocks or sedimentary host rocks. Silica-rich fluids precipitate in layers over millions of years, often colored by hematite/iron impurities.

Uses & applications

Primarily used for lapidary work, jewelry making (cabochons), and as a collector's specimen. Historically used for seals and talismans.

Geological facts

Agate is a variety of chalcedony. The reddish pocket in this specimen is specifically known as carnelian. It was highly prized in ancient Rome for signet rings because hot wax does not stick to it.

Field identification & locations

Identify by its waxy luster, translucency when held to light, and characteristic layered or pocketed structure. Often found in riverbeds or gravel pits in areas with basaltic history.