gemstone

Carnelian

Carnelian (microcrystalline quartz, SiO2)

Hardness: 6.5-7 on Mohs scale. Color: Orange to reddish-brown. Luster: Vitreous to waxy. Crystal system: Trigonal (microcrystalline). Fracture: Conchoidal. Transparency: Translucent to opaque.

Hardness: 6
Color: Orange to reddish-brown
Luster: Vitreous to waxy

Identified July 14, 2026More gemstone →

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Physical properties

Hardness: 6.5-7 on Mohs scale. Color: Orange to reddish-brown. Luster: Vitreous to waxy. Crystal system: Trigonal (microcrystalline). Fracture: Conchoidal. Transparency: Translucent to opaque.

Formation & geological history

Formed by the deposition of silica-rich groundwater in cavities within volcanic rocks (basalt or rhyolite). The reddish-orange color comes from iron oxide (hematite) impurities trapped within the silica structure.

Uses & applications

Primarily used in jewelry making for cabochons and beads, as well as for decorative carvings, seals, and historical amulets.

Geological facts

Carnelian is one of the oldest gemstones used in human history, dating back to 4500 BC in Mesopotamia. Romans used it for signet rings because hot wax does not stick to it.

Field identification & locations

Identified in the field by its waxy luster, orange color, and lack of visible crystal grains. Common locations include Brazil, India, Uruguay, and Madagascar.

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