mineral

Carnelian Agate

Chalcedony (Silicon Dioxide, SiO2)

Hardness: 6.5-7 (Mohs scale); Color: Orange to reddish-brown (caused by iron impurities); Luster: Vitreous to waxy; Crystal structure: Trigonal (cryptocrystalline); Cleavage: None; Specific gravity: 2.58-2.64

Hardness: 6
Color: Orange to reddish-brown (caused by iron impurities)
Luster: Vitreous to waxy

Identified April 5, 2026More mineral →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed as a cryptocrystalline variety of silica in cavities of volcanic and metamorphic rocks. The red/orange hue is derived from iron oxide minerals that leach into the silica during formation or through secondary weathering processes.

Uses & applications

Used primarily in lapidary arts for semi-precious jewelry, beads, cabochons, and ornamental carvings. Historically used for seal stones and amulets.

Geological facts

Carnelian has been used as a gemstone for over 4,500 years; ancient Egyptians believed it had protective properties for the soul after death. It is the translucent version of the red variety of Chalcedony, while opaque versions are known as Jasper.

Field identification & locations

Identify by its waxy luster and translucency when held to light. It is commonly found in riverbeds and on beaches (like those in Oregon or the Great Lakes) where water has tumbled the stones smooth.