Buried treasure is a naturally-generated structure added to Minecraft as part of 1.13 - The Update Aquatic.
Buried treasure consists of a hidden chest, buried several blocks underground. It can spawn in almost any biome, including Ocean Biomes. The chest can contain a wide variety of loot, including enchanted armor and tools. It usually contains diamonds, emeralds, gold ingots and prismarine crystals. There will always be a Heart of the Sea inside.
- Buried treasure is the only way to obtain a Heart of the Sea outside of the Creative mode inventory or commands.