How are coral islands different from all other types of islands?

Coral islands, also known as atolls, are formed primarily from the accumulation of coral debris and sand, distinguishing them from volcanic or continental islands that are formed through geological processes like volcanic activity or the rising of landmasses. Coral islands typically have a lagoon in the center and are often surrounded by a reef, providing unique ecosystems. Additionally, their formation is closely linked to the health of coral reefs, making them particularly vulnerable to climate change and ocean acidification. This sets them apart in terms of both origin and ecological significance.