A Bloomery is a type of furnace that was once widely used for smelting oxides. Bloomeries were the first smelters able to smelt iron. The result of using a bloomery is a mass of iron and slag called a bloom. This is called sponge iron, because it is porous like a sponge. Sponge iron is usually refined into wrought iron. Bloomeries are no longer used in smelting, because blast furnaces are better.