mineral

Carnelian (Chalcedony)

Silicon Dioxide (SiO2)

Hardness: 6.5–7 on Mohs scale; Color: Reddish-orange to brownish-red; Luster: Waxy to vitreous; Crystal Structure: Trigonal (microcrystalline); Cleavage: None; Specific Gravity: 2.58–2.64.

Hardness: 6
Color: Reddish-orange to brownish-red
Luster: Waxy to vitreous

Identified April 11, 2026More mineral →

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Physical properties

Hardness: 6.5–7 on Mohs scale; Color: Reddish-orange to brownish-red; 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 igneous rocks such as basalt. The reddish hue is caused by iron oxide (hematite) impurities.

Uses & applications

Primarily used in jewelry making, cabochons, beads, and as a popular semi-precious gemstone for collectors and metaphysical practitioners.

Geological facts

In ancient times, carnelian was used by Romans to create seal rings for wax impressions because hot wax does not stick to it. It has been used as a gemstone for over 4,500 years.

Field identification & locations

Identify by its translucence and warm reddish-brown hue. Commonly found in Brazil, India, Uruguay, and the United States (Oregon/Washington). In the field, look for smooth, waxy-textured pebbles in riverbeds or volcanic deposits.