Coral Block

Coral block is a solid block which comes in five variants: tube, brain, bubble, fire, and horn.

Dead coral block is a solid block which also comes in the same variants as coral blocks.

Obtaining
Coral blocks and dead coral blocks will only drop as an item if mined with any type of pickaxe. Otherwise, they will drop nothing.

Natural generation
Coral blocks naturally generate in coral reef structures. These are found in warm oceans.

Usage
Coral blocks and their dead variants can be used as building or decoration blocks.

Dead coral blocks
In order for coral blocks to stay alive, at least 1 of the blocks touching it must be water. If placed outside of water, it will irreversibly and instantly / eventually transform into its respective dead coral block.