Furnace

The furnace is a special block currently only available in the indev version of Minecraft. Before the furnace appeared, smelting was accomplished by creating a fire and dropping the ores into it. Now the furnace has its own smelting menu where several smelting operations can be done. It consists of one field for the object that will be smelted, one field for the output object and one field for a fuel. The fuel variates to either log, plank, stick, coal and also the items that you shouldn't use like chests and the workbench. Each operation takes 10 seconds

The furnace will take time to smelt objects, but it will also work when the smelting menu is closed, as long as there are still objects to smelt and there's enough fuel. If all objects are smelted, the furnace will stop using fuel. When the fuel runs out, the heat in the furnace, indicated by the flame icon, will slowly decrease and when it is gone, the furnace will become inactive. If a smelting process was running, it will be aborted and has to be started again from the beginning

The following smelting operations are known:

Currently a glitch exists which allows you to use the furnace as a light source. If you place a piece of fuel such as Planks in the furnace, then use a mining pick and pick up the furnace before the fire burns out. You will receive a furnace block.

When you place this block, you receive a permanently lit furnace which can then be used as a torch that does not require coal. The furnace will provide light that is the same as a normal torch, and will remain lit until you attempt to use the furnace for a smelting operation.

Glitch-lit furnaces will not stack with normal furnaces in your inventory, but however will stack with other glitch-lit furnaces.

Also, the glitch-lit furnaces do not allow you to smelt objects for free, they simply appear fully lit.