Conduit is crafted from one nautilus shell surrounded by eight heart of the sea fragments in a 3×3 grid — both ingredients are rare and require deep-ocean exploration to obtain. Heart of the sea drops only from buried treasure chests, and nautilus shells come from drowned mobs (rare drop) or fishing in ocean biomes. The block is one of the most expensive single recipes in vanilla.

When placed in a water source surrounded by a frame of prismarine blocks, dark prismarine, prismarine bricks, or sea lanterns (any combination), the block activates and grants nearby submerged players the Conduit Power effect: water breathing (no drowning), night vision underwater (full visibility), and haste (faster mining and attack speed). The minimum frame is sixteen prismarine-family blocks; larger frames extend the effect radius up to ninety-six blocks. The block also damages hostile mobs near it. Underwater bases at any depth become safe and productive thanks to this single block.