18K Gold Plated Sponge Red Coral with White Baroque Pearl Necklace, 18inch’s approximately. Irregular Stone size 18x27 mm sponge coral approximately. Sponge Coral is not actually made of sponge. It is a a type of coral. It has a sponge like appearance due to small holes that cover its surface. Coral is produced by small sea creatures called polyps. These creatures live in the holes. These small holes close in other forms of coral after the Polyps vacant, but in sponge coral they stay open. This is what give sponge coral its appearance. Sponge coral is can be found in the South China Sea, Indonesia and Taiwan. When viewed in its environment, Sponge coral can be identified by its fan like shape. Sponge coral and other corals can be used to make jewelry because they are not on the endangered species list. Red Sponge Coral is a good aid for meditation or visualization. Coral symbolizes life and blood force energy. Dark red coral is used for heating and stimulating the bloodstream. Pink shades restore harmony to the heart. It is used as an aid to depression, lethargy or deficient nutrition.