A rocklike deposit consisting of the calcareous skeletons secreted by various anthozoans.Coral deposits often accumulate to form reefs or islands in warm seas.

• 珊瑚一种礁石状沉积物，由各种珊瑚虫分泌的石灰质骨骼构成。在温暖海域中珊瑚沉积物常堆积形成沙洲或岛屿