mineral
Carnelian (Tumbled)
Carnelian (Chalcedony / Silicon Dioxide, SiO2)
Hardness: 6.5-7 (Mohs); Color: Orange to reddish-brown; Luster: Vitreous to waxy; Crystal Structure: Hexagonal (trigonal microcrystalline); Cleavage: None; Specific Gravity: 2.58–2.64
- Hardness
- 6
- Color
- Orange to reddish-brown
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 6.5-7 (Mohs); Color: Orange to reddish-brown; Luster: Vitreous to waxy; Crystal Structure: Hexagonal (trigonal microcrystalline); Cleavage: None; Specific Gravity: 2.58–2.64
Formation & geological history
Formed through the deposition of silica from groundwater into cavities in igneous and sedimentary rocks. Its reddish-orange color comes from impurities of iron oxide (hematite). Occurs in volcanic rocks and as water-worn pebbles in river beds.
Uses & applications
Popular for lapidary work, jewelry (beads, cabochons), carvings, and metaphysical collections.
Geological facts
In antiquity, carnelian was used for seals and signet rings because hot wax does not stick to it. It has been used as a gemstone for over 4,500 years, dating back to Ancient Egypt and the Indus Valley Civilization.
Field identification & locations
Identify by its uniform translucency and warm orange-red hue. It lacks the distinct banding found in banded agates. Commonly found in Brazil, India, Uruguay, Madagascar, and parts of the United States.
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