mineral

Carnelian Agate

Chalcedony (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 on Mohs scale. Color: Brownish-red to orange. Luster: Waxy to vitreous. Crystal structure: Cryptocrystalline. Cleavage: None. Specific gravity: 2.59-2.61.

Hardness: 6
Color: Brownish-red to orange
Luster: Waxy to vitreous

Identified August 31, 2026More mineral →

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Physical properties

Hardness: 6.5-7 on Mohs scale. Color: Brownish-red to orange. Luster: Waxy to vitreous. Crystal structure: Cryptocrystalline. Cleavage: None. Specific gravity: 2.59-2.61.

Formation & geological history

Forms as nodules in volcanic rocks or occasionally in sedimentary rocks. Groundwater rich in silica percolates through cavities, depositing layers of chalcedony. The red/orange color comes from iron oxide impurities.

Uses & applications

Commonly used in jewelry (cabochons, beads), carvings, and as a collector's stone. Historically used for signet rings and seals.

Geological facts

Carnelian was widely used during Roman times to make engraved gems for signet or seal rings for imprinting a seal with wax on correspondence or other important documents.

Field identification & locations

Identify by its waxy luster, conchoidal fracture, and characteristic reddish-orange to brownish-red color. Often found as water-worn pebbles in streams or beaches.