Updated by: Arabinda Naik
Corals of the remote geological past formed reef structures that were highly favourable sites for the accumulation of petroleum deposits. Thus, coral reefs are of much importance to oil industry. Large quantities of corals are shipped every year for the curio trade. The coral reefs serve as habitats for many plants and animals like sponges, molluscs, echinoderms, fishes, etc. Some coral reefs are used as habitations by man as well. Some corals are highly priced for their decorative value. Corallum rubrum is a precious stone in India and China and treated as auspicious. The red coral and organ pipe coral are used in some indigenous system of medicine in S. India. Chunks of coral skeleton belonging to species Porites are used as building material. Coral skeletons serve as raw material for the preparation of lime, mortar and cement because of their calcium carbonate and magnesium carbonate content. Coral skeletons are also helpful in making ridges that may act as natural barriers against sea erosion and cyclonic storms. Coral reefs serve as good nursery grounds for commercially important fishes. Reef fish varieties are more colourful than others.