Block of Iron – Official Minecraft Wiki
Usage []. Blocks of iron can be used to store iron ingots in a compact fashion.. Beacons []. 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.