Coral

Coral blocks are a decorative block found in lakes, oceans, or rivers. Coral blocks come in 4 colors, and also emit light.

Mining
Coral blocks can be mined with any pickaxe.

World Generation
Coral blocks can be found in bodies of water across the Overworld, and sometimes even underground though very rarely.

Miscellaneous
Coral blocks emit a light level of 11. It can be used for a solid mob proof floor, or just decoration.