Coral

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Coral
Chemical composition Aragonite (CaCO3)or conchioline
Crystal system Amorphous
Habit Branching, tree-like
Hardness 2.5 - 3.5
Refractive index 1.48 - 1.56
Specific gravity 1.37 - 2.60
Lustre Waxy
Mediterranen Red Coral Beads

Coral, Species:Scleronephthya


Coral is one of the few organic gems. It is the exoskeleton of colonial polyps. These are small animals that create their branching homes from calcium carbonate dissolved in sea water. The colors of gem coral range from a pale pink (angel-skin) to oranges and reds. Coral has been used throughout our history; it was pictured on a Summerian vase dated at 3000 BC It was traded between the Mediterranean and India at the time of the birth of Christ. Coral was introduced into Mesoamerica by the Spaniards. Native Americans used it extensively in jewelry. Coral was used in Roman times to protect children from danger. It is still worn in Italy today to protect from the evil eye.

G&G Articles on Coral 1934-1980

The GIA has published all the G&G's from 1934 until 1980 online. The organization of the list by subject was done by Joseph Gill.

Sources