Coral is the outer skeleton of sea polyps, made of calcium carbonate. It usually ranges from white to red, and grows in branches that look like underwater trees. Red, pink, and white corals are typically dense - while sponge and blue corals have small air pockets and interesting spotted patterns. Most coral for jewelry comes from the Mediterranean or the China Sea off Japan and Taiwan. Coral reefs in the South Pacific like the Great Barrier Reef grow a different species.
Value of coral
The price of coral remains low only because of stockpiles from up to 30-years ago. However, due to over-harvesting and environmental damage, coral is becoming rarer, and natural red coral is very expensive. Most red coral sold today has been dyed. Itís quite easy to tell this on bold red coral beads, but the pink and blue corals are usually color enhanced as well.
Fossil or agatized coral produces more subtle textures. This is ancient coral that has been replaced by agate so slowly that the flower-like patterns of the original coral remained intact. Though it will not make a bold statement like the red corals, fossil corals have their own charm. They are mostly beige; but the grayish flower patterns may have subtle hints of pink, blue, and other colors.
Traditional coral is usually used in its natural shape resembling a twiglet - where sponge coral is reconstituted into more-useable shapes. Sponge coral is then stabilized with a binding solution and polished to give a high luster. Without this processing, sponge coral would be very brittle and dull in appearance.