Coral island

A coral island is a type of island formed from coral detritus and associated organic material.^[1] It occurs in tropical and sub-tropical areas, typically as part of a coral reef which has grown to cover a far larger area under the sea. The term low island can be used to distinguish such islands from high islands, which are formed through volcanic action.^[2] Low islands are formed as a result of sedimentation upon a coral reef or of the uplifting of such islands.