Stony coral, also known as hard coral, is a type of marine organism that forms the backbone of coral reefs. These corals are made up of tiny, individual polyps that secrete calcium carbonate, creating a hard skeleton. This structure provides habitat and protection for various marine species, contributing to the biodiversity of ocean ecosystems. Stony corals thrive in warm, shallow waters and are often found in tropical regions. They rely on a symbiotic relationship with zooxanthellae, a type of algae that lives within their tissues. This partnership allows corals to obtain energy through photosynthesis, making them vital for the health of coral reefs.