Coral

Coral reefs are home to a significant per cent of marine plant and animal life. They are believed to have existed on and off for 500 million years but went through a number of  periods of dying off and then re-emerging. At present they are endangered by global warming and other effects of human enterprise. Red coral is a specific variety of coral that has been collected and used by humans for decorative purposes since ancient times. This red coral was found along the Mediterranean coast. The ancient Romans used it in trade with India where it was very popular. The use of coral continued through the Middle ages and Renaissance to modern times.
Bracelets like the red coral one pictured above can be found at Beadshaper