Sea Lantern

Sea Lantern is a light source that only appears underwater. The block gives off a light level of 15. The Sea Lantern also has its own animation.

Obtaining
Sea Lanterns can be crafted with Prismarine Shards and Prismarine Crystals, or found in Water Dungeons.

As a light source
Sea lanterns emit a light level of 15, which is the brightest possible light level in the game and the same as Glowstone.

As a source of prismarine crystals
When broken using anything other than a Silk Touch-enchanted tool, a sea lantern will drop 2–3 Prismarine Crystals. A Fortune enchantment increases the maximum by 1 per level up to a maximum of 5, with Fortune III increasing the chance of larger drops.