mineral

Carnelian Agate

Silicon Dioxide (SiO2)

Hardness: 6.5-7 on Mohs scale. Color: Orange to brownish-red. Luster: Vitreous to waxy. Crystal Structure: Trigonal (microcrystalline/cryptocrystalline). Cleavage: None. Specific Gravity: 2.58-2.64.

Hardness: 6
Color: Orange to brownish-red
Luster: Vitreous to waxy

Identified July 5, 2026More mineral →

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Physical properties

Hardness: 6.5-7 on Mohs scale. Color: Orange to brownish-red. Luster: Vitreous to waxy. Crystal Structure: Trigonal (microcrystalline/cryptocrystalline). Cleavage: None. Specific Gravity: 2.58-2.64.

Formation & geological history

Formed through the deposition of silica from groundwater in the cavities of igneous rocks, particularly volcanic lavas. The red color is caused by iron oxide impurities. Many specimens date from the Tertiary period.

Uses & applications

Used primarily in jewelry, cabochons, beads, and ornamental carvings. Historically used for signet rings and wax seals because hot wax does not stick to it.

Geological facts

Carnelian was revered by ancient Egyptians as the 'setting sun.' It was believed to protect the wearer and was buried with the dead to help them in their journey to the afterlife.

Field identification & locations

Identify in the field by its translucent orange-red color and conchoidal fracture. Commonly found in Brazil, India, Uruguay, and Madagascar. Collectors often find them as water-worn pebbles in riverbeds.