Carnelian
Variety of chalcedony
Common · SiO₂
A red-orange variety of chalcedony coloured by fine hydrous iron oxides. Forms in volcanic and sedimentary environments, and dull yellowish stones turn carnelian red when heated. Its even translucency made it a preferred material for carved seals and intaglios.
Identity
- Formula
- SiO₂
- Chemical class
- Silicate
- Mineral group
- Agate, Amethyst, Bloodstone, Chalcedony, Citrine, Jasper, Moss Agate, Onyx, Quartz, Rose Quartz, Smoky Quartz, Tiger's Eye
- Also known as
- Cornelian, Sard (darker brownish variety)
Crystallography
- Crystal system
- Trigonal
- Habits
- Massive, Nodular
- Fracture
- Conchoidal
Physical properties
- Mohs hardness
- 7
- Density
- 2.62 g/cm³
- Luster
- Vitreous, Waxy
- Colors
- red, orange-red, reddish brown
- Streak
- white
- Transparency
- Translucent, Opaque
Geology
- Origins
- Volcanic, Hydrothermal, Sedimentary
- Host rocks
- Volcanic rock, River gravels and sands
- Associated minerals
- Chalcedony, Quartz, Agate
- Found in
- Placer deposit
- Geography
- India, Brazil, Uruguay, Egypt, Madagascar
Classification
- Rarity
- Common
- Gem quality
- Yes
Sources
- Carnelian. Mindat.org (Hudson Institute of Mineralogy).
- Chalcedony. Mindat.org (Hudson Institute of Mineralogy).
- Carnelian. Gemdat.org (Hudson Institute of Mineralogy).
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