mineral

Carnelian

Carnelian (Silicon Dioxide, SiO2)

Hardness: 6.5–7 on the Mohs scale. Color: Translucent orange to reddish-brown. Luster: Vitreous to waxy. Crystal Structure: Trigonal (microcrystalline/cryptocrystalline). Cleavage: None (conchoidal fracture). Specific Gravity: 2.58–2.64.

Hardness: 6
Color: Translucent orange to reddish-brown
Luster: Vitreous to waxy

Identified March 19, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the deposition of silica-rich groundwater within the cavities (vesicles) of volcanic rocks (basalt). The orange color is caused by impurities of iron oxide (hematite). Specimens can be found in formations ranging from the Cenozoic era to older basaltic flows.

Uses & applications

Predominantly used as a gemstone in jewelry (cabochons, beads, and rings). Historically used for making cylinder seals, signet rings, and talismans. Occasionally used in ornamental carvings and as a collector's specimen.

Geological facts

In ancient Egypt, carnelian was associated with the blood of Isis and was frequently used in amulets like the 'Thet' (Knot of Isis). Many ancient cultures believed the stone calmed tempers and stopped bleeding. It is the translucent variety of chalcedony, whereas the opaque red variety is usually called jasper.

Field identification & locations

Identify in the field by its waxy luster, translucency (hold it to the light to see internal depth), and conchoidal fracture patterns. Found commonly in Brazil, India, Madagascar, and parts of the Pacific Northwest in the USA. Collectors look for uniform color and high translucency.