mineral

Carnelian Agate

Silicon Dioxide (SiO2) - variety of Chalcedony

Hardness: 6.5-7 (Mohs scale); Color: Translucent orange to reddish-brown; Luster: Waxy to vitreous; Crystal structure: Trigonal/Microcrystalline; Cleavage: None; Specific gravity: 2.58-2.64

Hardness: 6
Color: Translucent orange to reddish-brown
Luster: Waxy to vitreous

Identified April 7, 2026More mineral →

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Physical properties

Hardness: 6.5-7 (Mohs scale); Color: Translucent orange to reddish-brown; Luster: Waxy to vitreous; Crystal structure: Trigonal/Microcrystalline; Cleavage: None; Specific gravity: 2.58-2.64

Formation & geological history

Formed through the deposition of silica from groundwater into cavities of volcanic or sedimentary rocks. The orange color is caused by iron oxide (limonite or hematite) impurities. Most specimens are millions of years old.

Uses & applications

Predominantly used as a gemstone for jewelry (cabochons, beads), decorative carvings, and as a popular specimen for rock collectors and lapidary hobbyists.

Geological facts

Carnelian has been used as a gemstone since antiquity; the ancient Egyptians used it in amulets and it was frequently used for signet rings because hot wax does not stick to it.

Field identification & locations

Identify in the field by its translucency when held to light, its waxy luster, and its smooth, rounded shape if found as a beach pebble. Commonly found on beaches in the Pacific Northwest and in riverbeds.

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