Mineral (specifically a variety of Chalcedony, which is a cryptocrystalline quartz)

Carnelian

Carnelian (a variety of Chalcedony, SiO ₂)

Hardness: 6.5-7 on the Mohs scale. Color: Translucent reddish-brown to orange-red. Luster: Vitreous (glassy) to waxy. Crystal Structure: Trigonal, but typically massive and cryptocrystalline (crystals are too fine to be seen without high magnification). Specific Gravity: 2.58-2.64.…

Hardness: 6
Color: Translucent reddish-brown to orange-red
Luster: Vitreous (glassy) to waxy

Identified July 26, 2025More mineral (specifically a variety of chalcedony, which is a cryptocrystalline quartz) →

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Physical properties

Formation & geological history

Carnelian is a form of chalcedony, a microcrystalline variety of quartz. It forms from silica-rich solutions that precipitate in cavities of volcanic, sedimentary, or metamorphic rocks, often within geodes or as vein fillings. The reddish-brown to orange color is due to the presence of iron oxide impurities. Its formation is generally secondary at low temperatures and pressures. Geological age varies widely depending on the host rock.

Uses & applications

Primarily used as a gemstone in jewelry (cabochons, beads, carvings). Also used in ornamental objects and for collecting. Historically, it was popular for signet rings and seals.

Geological facts

Carnelian has been used since antiquity, with significant historical importance in ancient Egypt, Rome, and Greece. It was often used for seals, signet rings, and intaglio carvings due to its durability and the way wax does not stick to it. In the Middle Ages, it was believed to ward off evil and purify blood. It's often associated with courage and vitality.

Field identification & locations

In the field, carnelian can be identified by its distinctive reddish-orange to brown color, waxy to vitreous luster, and its hardness (it will scratch glass). It typically appears as nodules or in vein fillings. It's often found in association with other chalcedony varieties, agates, and jasper in volcanic regions, alluvial deposits, and weathered sedimentary rocks. Major sources include India (especially the Deccan Traps), Brazil, Uruguay, Madagascar, and parts of the United States.

Other mineral (specifically a variety of chalcedony, which is a cryptocrystalline quartz) specimens

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Red Jasper

Silicon Dioxide (SiO2) with Iron Oxide inclusions

mineral

Jasper

Silicon Dioxide (SiO2) with impurities (mostly Iron Oxides)

sedimentary

Dalmation Stone (often called Dalmatian Jasper)

Antiperthite-rich Microgranite

igneous

Mixed collection of minerals and rocks (Jasper, Carnelian, Granite, and Quartz)

Silicon Dioxide (SiO2) with varying impurities for silicates and igneous aggregates

igneous, sedimentary, and metamorphic

Leopard Skin Jasper

Chalcedony (cryptocrystalline Quartz)

Mineral

Carnelian

Carnelian (a variety of Chalcedony, which is a microcrystalline quartz, SiO2)

Mineral (variety of Chalcedony)