mineral

Carnelian Agate

Chalcedony (SiO2) with iron oxide inclusions

Hardness: 6.5–7 (Mohs); Color: Orange, reddish-brown, pale orange; Luster: Vitreous to waxy; Crystal structure: Hexagonal (trigonal); Cleavage: None; Specific gravity: 2.58–2.64

Hardness: 6
Color: Orange, reddish-brown, pale orange
Luster: Vitreous to waxy

Identified April 11, 2026More mineral →

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Physical properties

Hardness: 6.5–7 (Mohs); Color: Orange, reddish-brown, pale orange; Luster: Vitreous to waxy; Crystal structure: Hexagonal (trigonal); Cleavage: None; Specific gravity: 2.58–2.64

Formation & geological history

Formed in volcanic and sedimentary rocks where silica-rich groundwater fills cavities, often as geode linings or nodules. Its color comes from iron oxide-rich impurities that have petrified over millions of years.

Uses & applications

Commonly used in jewelry (beads, cabochons), ornamental carvings, and gemstone therapy. Historically used for signet rings and wax seals due to its lack of adhesion to hot wax.

Geological facts

Ancient Romans and Greeks used carnelian for intaglios and cameos. It is associated with the Prophet Muhammad, who was said to wear a carnelian seal ring.

Field identification & locations

Identify by its waxy luster, translucency, and inability to be scratched by a steel knife. It is frequently found in riverbeds and on beaches as water-worn pebbles.

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