mineral

Carnelian (Carnelian Agate)

Cryptocrystalline Quartz (SiO2 with Hematite impurities)

Hardness: 6.5-7 Mohs; Color: Orange, reddish-brown, semi-translucent; Luster: Waxy to vitreous; Crystal Structure: Hexagonal (trigonal microcrystalline); Cleavage: None; Fracture: Conchoidal; Specific Gravity: 2.58-2.64.

Hardness: 6
Color: Orange, reddish-brown, semi-translucent
Luster: Waxy to vitreous

Identified July 4, 2026More mineral →

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Physical properties

Formation & geological history

Formed within volcanic cavities or sedimentary rocks through the precipitation of silica from groundwater at low temperatures. The red-orange color comes from iron oxide (hematite) impurities. Often found as water-worn pebbles in stream beds.

Uses & applications

Used primarily for lapidary work, jewelry (beads, cabochons, signet rings), and as a collector's specimen. Historically used for seals and amulets.

Geological facts

Carnelian is one of the oldest gemstones used in jewelry, dating back to at least 4500 BC. Ancient Romans and Egyptians used it extensively for signet rings and decorative carvings because wax does not stick to it.

Field identification & locations

Identified by its distinctive waxy luster, orange-red translucency, and conchoidal fracture. The coordinates provided (near El Paso, TX) are in an area geologically rich in agates and chert, particularly in the Rio Grande gravels and volcanic formations of the Chihuahua Desert.

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