Minecraft wiki entry for Block_of_Diamond, associated text: Blocks of diamond can be used to "power" a beacon. The beacon can be powered by a 3×3 square of diamond 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 diamond blocks, as they may also contain blocks of iron, blocks of gold, blocks of netherite, and blocks of emerald.