Gemstone profile and identification guide
Red Coral
Red coral is an organic gemstone material with longstanding decorative and cultural use.
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Overview
Red coral is an organic gemstone material with longstanding decorative and cultural use.
Did you know? High-quality untreated red coral is increasingly limited and tightly regulated.
Use this profile as a collector reference and educational guide for quick on-page comparison, then validate with the interactive identification system.
Identification
Name: Red Coral
Scientific classification: Organic Gem Material (Coral)
Hardness: 3.5 Mohs
Transparency: opaque
Lustre: waxy
Crystal system: Biogenic aggregate
Primary colour: Red
Secondary colour: Orange Red
Colour family: Reds
Porosity and structure help identify coral and assess dye/stabilization.
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.
Trade-name and treatment-sensitive entries include explicit disclosure notes where applicable.
Physical Properties
Hardness category: soft
Hardness value: 3.5 Mohs
Chemical composition: Calcium carbonate with organic matrix
Crystal system: Biogenic aggregate
Common locations: Mediterranean and Pacific coral sources; processed through global trade centers
Learn more: Gem-A gemstone education resources.
Colour Variations
Red coral in natural to enhanced red tones used in traditional jewelry.
Optical effects: None specified in the current dataset.
Detailed Gemology
Mineral species: Coral-based organic material
Mineral group: Organic gem materials
Chemical formula: Calcium carbonate with organic matrix
Mohs hardness: 3.5
Crystal system: Biogenic aggregate
Lustre: waxy
Transparency: opaque
Streak: White
Cleavage: Not applicable
Fracture: Splintery to uneven
Specific gravity: 2.60-2.70
Refractive index: Variable spot values, often near 1.53
Optical phenomena: None typically diagnostic
Colour range: Red to orange-red
Common inclusions: Growth channels and organic texture
Geological environment: Marine biogenic reefs/habitats
Principal mining regions: Mediterranean and Pacific coral sources; processed through global trade centers
Important commercial sources: Red coral trade requires legal sourcing documentation and treatment disclosure
Historical significance: Major historical ornamental material in Mediterranean and Asian markets.
Common treatments: Dyeing, bleaching, and stabilization are common.
Synthetic or imitation forms: Dyed bone, resin, and plastic imitations are common.
Common look-alikes: Dyed howlite, red glass, synthetic composites
Jewellery uses: Used in beads, carvings, cabochons, and traditional ornaments.
Care recommendations: Red Coral should be cleaned with lukewarm water, mild soap, and a soft brush. At Mohs 3.5 in the Biogenic aggregate system, avoid steam cleaners, harsh chemicals, and high-impact wear. Protect cleavage directions from sharp knocks during wear and setting.
Cross-check profile data with GIA Gem Encyclopedia and Mindat entry for Red Coral.
Formation
Biogenic coral skeleton growth in marine environments.
Origin
Red coral trade requires legal sourcing documentation and treatment disclosure
Uses
Best for: Used in beads, carvings, cabochons, and traditional ornaments.
Ideal uses: Occasional-wear pieces and cultural jewelry forms.
Care
Red Coral should be cleaned with lukewarm water, mild soap, and a soft brush. At Mohs 3.5 in the Biogenic aggregate system, avoid steam cleaners, harsh chemicals, and high-impact wear. Protect cleavage directions from sharp knocks during wear and setting.
Need another candidate? Use advanced gemstone search or return to the identification guide.
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Commonly confused gemstones
Red Coral FAQ
How can I identify Red Coral?
Compare hardness (3.5 Mohs), crystal system (Biogenic aggregate), colour profile, and lustre (waxy) with your sample. Then cross-check related gemstones listed above.
What colour range does Red Coral appear in?
Red coral in natural to enhanced red tones used in traditional jewelry.
Where is Red Coral commonly used?
Occasional-wear pieces and cultural jewelry forms.. For maintenance, follow the care guidance in this profile.
Scientific References
GIA: general gemstone identity (reviewed) - Batch 08 factual verification pass.
Gem-A: gemological terminology and testing references (reviewed) - Batch 08 factual verification pass.
Mindat: mineral species and principal localities (reviewed) - Batch 08 factual verification pass.
International Gem Society: gem trade context and treatment overview (reviewed) - Batch 08 factual verification pass.