Furnace

A Furnace is a special block currently available in all Minecraft versions except for Classic. Furnaces can naturally occur in NPC Villages. Before the furnace appeared, smelting was accomplished by creating a fire and dropping the ores into it. The furnace, when right-clicked, has its own menu where heating operations can be done. It consists of one field for the object that will be smelted, one field for the fuel and one field for the output object. Wood, Wooden Planks, Wooden Pressure Plate, Coal, Charcoal, Blaze Rods and Lava Buckets (plus Chests, Crafting Tables, Bookshelves, Sticks, Saplings, Jukeboxes, Note Blocks, Locked Chests, Wooden Stairs, Trapdoors and Fences, none of which are very efficient) are all fuels. Each smelting operation takes 10 seconds. Furnaces resemble Dispensers, but the two blocks have different uses and crafting recipes.
A pickaxe is required to collect the furnace.
Smelting will continue to work when the smelting menu is closed, as long as there are still objects to heat and there is enough fuel. The fire icon diminishes to represent the fuel burn time. When the fire icon diminishes fully, another fuel item is consumed and the heat is refilled. If all objects are smelted, the furnace will stop using additional fuel. The furnace will also stop if the output field contains a full stack, or if it contains a different item (e.g., trying to smelt gold ore with iron ingots in the output). If there is no fuel left, the furnace will become inactive. If a smelting process was running, it will be cancelled and must be redone.
Gold and Iron ores can be smelted into ingots. Furnaces can also be used to smelt Redstone Ore, Lapis Lazuli Ore, Coal Ore, and Diamond Ore (obtained with the Silk Touch enchantment) and returns 1 Redstone, Lapis lazuli, Coal, or Diamond respectively.