Fire

Fire is a block that was first seen in Indev. It has an animated face on all four sides, and two faces on the inside at slants. Fire is not usually created naturally in a map, with the exception being in The Nether, it will only be created if the player or a Ghast causes it or Lava burns a flammable object. Fire produces 15 units of light.

Fire is only available for use in Indev, Infdev, Alpha, and Beta. It cannot be directly placed (although it could be in an old Indev version designed to test out fire), but rather by using Flint and Steel. When placed, the fire will burn for a short, randomly determined period of time. If nothing flammable is next to it, the flames will die out. Wood, Logs, Leaves, Cloth, and Bookcase blocks are all flammable, while TNT will detonate if exposed. Fire will spread over flammable surfaces, slowly causing all the blocks it can reach to burn away. Fire can climb up walls, across floors and ceilings and over small gaps.

As one would expect, any mob (including the player) will be lit on fire if exposed to it. The fire will obstruct the player's view slightly and they will slowly lose life. The fire will burn out after a while, but it is a good idea to try and jump into some Water as soon as possible. A water bucket functions as a portable fire extinguisher as a player who is on fire can dump the water at their feet to put out the fire instantly. If there's no water nearby, the player could also press 'ESC' for the pause screen, wait a few seconds and go back to game. Most of the time, the player won't lose anymore health, and the flames will go out after some seconds.

Fire can be used as an attack against mobs. Lighting dropped items or blocks on fire will cause them to burn away. This trick can be used to dispose of materials quickly. Anything that touches Lava, whether it is a mob or a dropped object, will be lit on fire, although lava will not set off TNT.

Punching or hitting the side the fire is on will extinguish the fire on the side that was hit. Water, sand, and gravel will also extinguish fire.

Eternal Fire
In Beta (1.0 to 1.2_02), a flammable block, like wood, may burn continuously when its sides are surrounded by non-flammable blocks, like stone or dirt (the bottom is not necessary, though it is best not to have anything explicitly flammable underneath). A fire will only stay burning at the top of a flammable block, not on the sides or the bottom. Once the fire is burning - and has continued to do so for ten seconds or more without consuming the block beneath - you may remove all the adjacent blocks, and it will keep going forever. If the block burns away, simply replace and re-ignite until it works. Alternatively, you can punch out any adjacent fires that appear instead of surrounding the block. Eternally burning wood is fixed in Minecraft beta 1.3.

It is also possible to make larger blocks of endless fire by putting flammable blocks diagonally adjacent to a block that is burning continuously. Since the already-burning block counts as non-flammable - it is already on fire - the adjacent blocks may also burn continuously. By igniting multiple blocks this way, you can make a grid of diagonally adjacent burning blocks, which you can then fill with more flammable blocks to complete the surface.

Netherrack, found in The Nether, burns infinitely. This is a much easier way to obtain eternal fire.

Eternally Burning Trees
Due to a bug (fixed in 1.3), if a Flint and Steel is used to light a tree on fire, it becomes possible for pieces of the log to burn eternally. See "Eternal Fire" above. You can create this effect by extinguishing (punching) the fire on the sides of the trunk but leaving the top alight. Wood blocks can also be burned eternally in fireplaces, creating light for a room.

As a Trap or Fuse
Using eternally burning fires can be effective as cheap mob traps/defenses, but will sometimes burn the loot. Also, since fires generally spread slowly, they can be used as a fuse to set off TNT or to release water/lava, though this is unreliable since fire does not always travel predictably. Eternally burning blocks can also be placed around a perimeter, setting mobs and animals on fire that try to enter the premises.

Chainmail Armor
It is possible to craft Chainmail Armor out of fire blocks. It is only possible to get actual fire blocks in the players inventory by means of using the /give command or an Inventory editor.

Trivia

 * When smoke hits water it hisses just like when water hits fire.
 * Since alpha version 1.2.6, during a biome's creation (Starting a new world or exploring) a random forest fire may start (Although this is very rare). This was caused by the addition of above-ground lava pools.
 * Fire is often used to make a fireplace in a house, lighting logs or netherrack.
 * When playing on Peaceful mode, if you start burning but get away from the fire source, you can't die from the burning, as your health regenerates at a slightly greater speed than the damaging.
 * Fire spreads at the bottom of trees, slanting in one direction.

Feuer