Minecraft wiki entry for Block_of_Iron, associated text: Blocks of iron can be used to "power" a beacon. The beacon can be powered by a 3×3 square of iron blocks underneath it, and can optionally also include a 5×5, 7×7 and 9×9 layer in the shape of a pyramid under the original layer to increase the effects from the beacon. The layers do not have to be entirely iron blocks, as they may also contain blocks of gold, blocks of diamond, blocks of netherite or blocks of emerald.