Organic Gems · rare

Red Coral

Precious coral is formed from the skeletons of marine animals. Red coral from the Mediterranean has been prized for jewelry for thousands of years.

Red Coral specimen reference photo: Corallium rubrum (polished precious red coral) (Mediterranean Sea, offshore Italy) 2
Photo: James St. John · Wikimedia Commons · CC BY 2.0

Red Coral properties at a glance

TypeOrganic Gems
Chemical formulaCaCO3
Mohs hardness3.5
Crystal systemtrigonal
Lustervitreous
StreakWhite
CleavageNone
FractureUneven
Specific gravity2.65
Transparencyopaque
Common colorsRed, Pink, Orange, White
Rarityrare

Geology & background

Forms from the skeletons of marine polyps (coral animals) that accumulate calcium carbonate over time.

Mediterranean red coral has been traded since ancient times and was highly valued in ancient Rome, Greece, and Egypt.

How to identify Red Coral

  • Check whether the specimen's color and texture match typical Red Coral examples.
  • Photograph a fresh surface in natural light and avoid shadows, glare, or wet surfaces.
  • Use hardness, streak, luster, grain size, and locality together; no single trait is enough for every specimen.

Where Red Coral is found

Red Coral is reported from multiple localities or geological settings. Exact locality should be verified from specimen provenance, maps, or field notes.

How much is Red Coral worth?

Entry-level specimen$50
Typical collector specimen$300
Premium specimen$3000+

Value depends on size, condition, color, crystal quality, locality, rarity, preparation, and provenance. Treat this as educational guidance, not an appraisal.

Common uses

  • Jewelry
  • Decorative objects

Interesting facts

  • Takes decades to centuries to form
  • Was once thought to be a plant
  • Ancient Romans hung coral around children's necks for protection

Care & safety

Treat Red Coral as a collector specimen unless hardness, cleavage, and fracture are confirmed.

Avoid inhaling dust. Do not cut, grind, or polish unknown specimens without eye protection and a properly rated respirator.

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