gemstone

Carnelian (Chalcedony)

SiO2 (Silicon Dioxide with iron oxide inclusions)

Hardness: 6.5-7 on Mohs scale. Color: reddish-orange, brownish-red, to translucent amber. Luster: waxy to vitreous. Crystal system: trigonal/microcrystalline. Cleavage: none, shell-like (conchoidal) fracture. Specific gravity: 2.58-2.64.

Hardness: 6
Color: reddish-orange, brownish-red, to translucent amber
Luster: waxy to vitreous

Identified July 25, 2026More gemstone →

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Physical properties

Formation & geological history

Forms at relatively low temperatures through the deposition of silica-rich solutions within gas cavities (vesicles) of volcanic rocks and sedimentary environments over millions of years.

Uses & applications

Popular gemstone used in jewelry making, lapidary art, carvings, beads, and metaphysical/mineral collections.

Geological facts

Carnelian has been used by humans for over 4,500 years. Ancient Romans used carnelian stones in signet rings for carving seals because hot wax does not stick to it.

Field identification & locations

Identify in the field by its distinctive warm reddish-orange translucency, waxy surface sheen, and extreme durability against scratching glass. Commonly found in gravel beds, volcanic terranes, and beach deposits in places like India, Brazil, Madagascar, and the Pacific Northwest USA.

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