gemstone

Carnelian

SiO2 (Silicon Dioxide with Iron Oxide impurities)

Mohs hardness of 6.5-7, waxy to vitreous luster, translucent to semi-transparent, reddish-orange to brownish-red color, trigonal microcrystalline structure, conchoidal fracture.

Identified July 23, 2026More gemstone →

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Physical properties

Mohs hardness of 6.5-7, waxy to vitreous luster, translucent to semi-transparent, reddish-orange to brownish-red color, trigonal microcrystalline structure, conchoidal fracture.

Formation & geological history

Formed by low-temperature precipitation of silica-rich solutions in cavities of volcanic, sedimentary, or metamorphic rocks. Color is caused by trace iron oxide impurities.

Uses & applications

Used in lapidary work, jewelry (beads, cabochons, carvings, seal rings), and as a popular collectible gemstone.

Geological facts

Carnelian has been used in jewelry making for over 4,500 years. Ancient Romans used it to craft signet rings for sealing wax because hot wax does not stick to carnelian.

Field identification & locations

Identified by its distinctive warm orange-red translucent body and smooth, waxy luster. Commonly found along stream beds, gravel deposits, and volcanic regions in Brazil, India, Madagascar, and the US (Oregon, Washington).

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Diamond and Gold Jewelry

Carbon (Diamond) / Au (Gold)

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Ammolite

Ammolite (Biogenic Aragonite with trace elements; fossils of Placenticeras meeki and Placenticeras intercalare)

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Cubic Zirconia (simulant) or Diamond

ZrO2 (Cubic Zirconia) or C (Diamond)

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Red Jasper

Silicon Dioxide (SiO2) with Hematite inclusions

sedimentary

Cubic Zirconia (or possibly Diamond)

Zirconium dioxide (or Carbon)

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Faceted Gemstone

Unknown transparent mineral, possibly Diamond (C), Cubic Zirconia (ZrO2), Quartz (SiO2), or Glass

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