mineral

Carnelian

Carnelian (Chalcedony/Quartz, SiO2)

Hardness: 6.5-7 (Mohs); Color: Orange-red to brownish red; Luster: Waxy to vitreous; Crystal structure: Trigonal/Microcrystalline; Cleavage: None; Specific Gravity: 2.59-2.61

Hardness: 6
Color: Orange-red to brownish red
Luster: Waxy to vitreous

Identified June 28, 2026More mineral →

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Physical properties

Hardness: 6.5-7 (Mohs); Color: Orange-red to brownish red; Luster: Waxy to vitreous; Crystal structure: Trigonal/Microcrystalline; Cleavage: None; Specific Gravity: 2.59-2.61

Formation & geological history

Formed through the percolation of silica-rich groundwater through porous rock or volcanic cavities. It can form in various geological ages but is often found in sedimentary environments or volcanic basalt.

Uses & applications

Primarily used in jewelry (cabochons, beads, pendants), ornamental carvings, and seal stones since ancient times. It is also popular in holistic/spiritual practices.

Geological facts

Carnelian was used by the Romans for signet rings because hot wax does not stick to it. It has been found in archaeological sites dating back to the Neolithic period (4th-5th millennium BC).

Field identification & locations

Identify by its translucent waxy luster and brownish-red to orange hue. Common locations include Brazil, India, Madagascar, and Uruguay. Field collectors look for cryptocrystalline quartz nodules in basalt or gravel beds.