Gemstone profile and identification guide
Carnelian
Carnelian is an orange to red chalcedony variety of quartz, typically translucent with a waxy to vitreous surface lustre.
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Overview
Carnelian is an orange to red chalcedony variety of quartz, typically translucent with a waxy to vitreous surface lustre.
Did you know? Carnelian was widely used for Roman and Islamic engraved seals.
Use this profile as a collector reference and educational guide for quick on-page comparison, then validate with the interactive identification system.
Identification
Name: Carnelian
Scientific classification: Silicate (Chalcedony Quartz)
Hardness: 7 Mohs
Transparency: translucent
Lustre: waxy
Crystal system: Trigonal (microcrystalline aggregate)
Primary colour: Orange
Secondary colour: Red
Colour family: Oranges & Yellows
Distinguished by translucent orange-red body colour, chalcedony texture, and Mohs 7 hardness.
Verification Status
Status: verified-core-fields
Reference priority: GIA, Gem-A, Mindat, International Gem Society
Core identity, locality, and physical-property fields reviewed against standard gemological references.
Values are given as practical gemological ranges where appropriate.
Physical Properties
Hardness category: hard
Hardness value: 7 Mohs
Chemical composition: Silicon dioxide (SiO2)
Crystal system: Trigonal (microcrystalline aggregate)
Common locations: India, Brazil, Uruguay, Madagascar, Egypt
Learn more: Gem-A gemstone education resources.
Colour Variations
Translucent orange to red chalcedony coloured by iron oxides.
Optical effects: None specified in the current dataset.
Detailed Gemology
Mineral species: Quartz (chalcedony variety)
Mineral group: Quartz group
Chemical formula: Silicon dioxide (SiO2)
Mohs hardness: 7
Crystal system: Trigonal (microcrystalline aggregate)
Lustre: waxy
Transparency: translucent
Streak: White
Cleavage: None
Fracture: Conchoidal
Specific gravity: 2.58-2.64
Refractive index: 1.53-1.54
Optical phenomena: None typically diagnostic
Colour range: Orange, red, reddish brown
Common inclusions: Iron-oxide clouds, banding, healed fractures
Geological environment: Volcanic and sedimentary chalcedony deposits
Principal mining regions: India, Brazil, Uruguay, Madagascar, Egypt
Important commercial sources: Commercial carnelian is sourced mainly from India and Brazil, with additional supply from Uruguay and Madagascar
Historical significance: Important historical seal and amulet material in multiple ancient cultures.
Common treatments: Heat enhancement and dyeing are common in trade.
Synthetic or imitation forms: Dyed chalcedony and glass imitations are common.
Common look-alikes: Dyed agate, jasper, orange glass
Jewellery uses: Used in beads, signet-style cuts, cabochons, and engraved intaglios.
Care recommendations: Durable for most jewellery at Mohs 7. Clean with mild soap and avoid harsh chemicals on treated stones.
Cross-check profile data with GIA Gem Encyclopedia and Mindat entry for Carnelian.
Formation
Forms as chalcedony in silica-rich cavities and veins; iron oxidation controls orange to red coloration.
Origin
Commercial carnelian is sourced mainly from India and Brazil, with additional supply from Uruguay and Madagascar
Uses
Best for: Used in beads, signet-style cuts, cabochons, and engraved intaglios.
Ideal uses: Beads, seals, and cabochons emphasizing even warm body colour.
Care
Durable for most jewellery at Mohs 7. Clean with mild soap and avoid harsh chemicals on treated stones.
Need another candidate? Use advanced gemstone search or return to the identification guide.
Related gemstones by colour
Related gemstones by hardness
Gemstones from the same mineral family
Commonly confused gemstones
Carnelian FAQ
How can I identify Carnelian?
Compare hardness (7 Mohs), crystal system (Trigonal (microcrystalline aggregate)), colour profile, and lustre (waxy) with your sample. Then cross-check related gemstones listed above.
What colour range does Carnelian appear in?
Translucent orange to red chalcedony coloured by iron oxides.
Where is Carnelian commonly used?
Beads, seals, and cabochons emphasizing even warm body colour.. For maintenance, follow the care guidance in this profile.
Scientific References
GIA: general gemstone identity (reviewed) - Batch 01 factual verification pass.
Gem-A: gemological terminology and testing references (reviewed) - Batch 01 factual verification pass.
Mindat: mineral species and principal localities (reviewed) - Batch 01 factual verification pass.
International Gem Society: gem trade context and treatment overview (reviewed) - Batch 01 factual verification pass.