Minecraft/Furnace

Use
It can be used to smelt and cook items, allowing the player to turn metals into ingots as well as cook food. However needs fuel and something to smelt. If there is fuel inside it, but nothing to smelt, the fuel is not used up. If the items inside have been smelted, but a consumed peice of fuel is still providing fuel, the provided fuel will drain, so you should top up the smelt slot as soon as possible to avoid waste. If the fuel runs out, the smelting progress will deplete until it empties completely.

It takes exactly ten seconds to smelt any item.