Iron Block.

Iron is a common block and can be smelted in a furnace to get iron bars for making many tools and weapons.

Iron can be bought for around 100 gold pieces each at the Block Shop. You can also sell them for around 34 gold pieces. If you are in need of crafting tools, this is best to buy iron blocks with any kind of fuel instead of iron bars.

Iron can be combined with carbon in a furnace to make steel.