Furnace

The furnace is a special block currently only available in the indev and infdev versions 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

Furnaces take more time to destroy than other blocks, making them a very valuable building material. However, since they require 8 blocks to craft, they are difficult to amass in any large quantities.

A glitch is known wherein a player destroys a furnace block in use (I.E. smelting iron). the furnace will be able to be picked up, and when placed down, will still be alight for an indefinite period of time. If you right click on it, however, it will have nothing in it, making it serve a dual purpose of destroying items and providing light without fuel.

The following smelting operations are known: