Lava

Lava is a fluid block which emits light and sets things on fire.

Natural occurrence
Lava primarily occurs in large pools (magma pools) deep underground, on levels 0 through 10. It can also occur as lava rivers from a single spring block, most commonly in caves but also above ground (where it is a common cause of natural forest fires).

Since Alpha 1.2.6, Lava also occurs in lakes. They are rare and can be found at any elevation within any biome, and can cause forest fires. Lava lakes vary in size and depth, and will carve out a small ceiling area above them when generated below the surface.

In the Nether, lava is extremely common; it forms the world's ocean instead of water, and also is often found in streams falling from the ceiling.

Burning

 * Most entities, including players and mobs, will take damage every second from being in contact with lava, in addition to being set on fire. If the player is able to reach or pour water in time, the fire will be put out.


 * However, wood logs and planks and wool blocks are flammable (wood stairs, plates, fences, and half-blocks are not). If flammable blocks are within about 2 meters of lava, they will catch fire. Non-flammable blocks can block this effect. The “embers” or “fireballs” which fly out of lava are purely decorative and do not directly cause fires.


 * A bucket of lava can be used to fuel a furnace long enough to smelt 100 blocks. This consumes the bucket as well as the lava and so is not generally considered practical.


 * Warning: If you are playing on peaceful difficulty, it is still possible to die. On some occasions the regenerating hearts and loss of hearts from the lava will simply counteract each other, and the player's hearts will fluctuate by only a half a heart, keeping them alive and giving them longer to find water. It is unknown if this is a bug or if it was intended.

Flowing
Lava flows far slower than Water, and sometimes sourceless lava flows will linger for a very long time. See Fluids for detailed information on how lava and water flow.

The interaction of lava and water:
 * If lava flows horizontally into water, Cobblestone is created.
 * If lava flows vertically into water, the water is removed.
 * If water flows horizontally into lava, a hiss and puff of smoke occur but nothing changes.
 * If water flows vertically into lava, Cobblestone or a hiss may result.
 * If water flows into a lava spring then Obsidian is created.

The primary natural source of obsidian is rivers flowing onto the surface of magma pools in deep caves; care should be taken if mining these since there is usually a layer of lava under the obsidian.

Lava which is flowing will destroy the following in its path: wheat, reeds, flowers, mushrooms, levers, both types of torches, redstone wire,and rails. Note it doesn't flow over plates, fences, or even wood or wool blocks.

If lava falls onto redstone wire bordered by water, the redstone turns into obsidian, with no loss of lava. This is considered a bug; see the section on Obsidian for more information.

Using a redstone wire, a one-block lava flow can be redirected by supplying power to the spring block, which will cause it to reset the flow towards the now-nearest terrain depression. This is further elaborated in this thread. It cannot, however, be reversed. This re-calculation is made because redstone wire when toggled changes the block from redstone(on), to redstone(off). Whenever a block updates on any side of lava, the lava re-calculates where to flow, but does not cut off its current direction of flow.

Uses
You can collect and place Lava springs using a Bucket. As with Water, you can only harvest these springs, not the flowing lava coming from them. Unlike water springs, lava springs cannot be duplicated; there is no way to create lava and it is not a renewable resource.

Lava can be used to make obsidian, as lighting or traps, and to fuel furnaces.

History




Classic
In Classic, lava spreads by duplicating itself to open horizontal and downwards squares like Water. Lava is slower, though, and can be easily outrun. A quick player can block the flow of lava by building a dam. However, if the lava wave is large, a player may not be able to build fast enough. Also like water, lava slows down the player moving through it but it does so to a greater extent. Lava is also more opaque than water and is harder to see through while you are submerged. You cannot see through lava from outside it. At the bottom of the map, lava can be found directly above bedrock in a different form, as it will trap the player and prevent the player from leaving unless water is let in and collides with it, or the player hits R and respawns, or if the player places a sand block, letting it drop into the lava. If water is let into the area where the Lava is, the lava will form Stone, this will allow the stone block to be removed to expose Bedrock underneath.

Survival
Since Infdev, lava flows more realistically across surfaces but not as much as water does. Lava will flow for a total distance of 3 blocks away from the source block (further in The Nether). Just like water, lava will flow in a single line towards the nearest terrain depression within four blocks. Items thrown into lava flows will disintegrate. Though most objects burn instantaneously, obsidian takes a few seconds longer.

The amount of damage has been reduced to a half of a heart being removed for every second the player is in lava, in addition to the damage from fire. Lava is no longer present at the bottom of maps in this mode. Lava can melt ice and snow, much like torches can, but melt a larger area. Lava is luminous and a large lava flow is visible in the dark from quite a distance.

The creation of Obsidian was added in Alpha v.1.0.6_03.

In Beta, lava is less reactive with horizontal water flows. Lava flows or pools without a source will degrade to dirt after a given time period.

Since the 0.0.19a client update on June 20, 2009, Lava's texture became animated.

As of Seecret Friday Update 9, buckets of lava can be used to fuel a Furnace for 100 smelt; however, the bucket itself will be consumed in the process. Before the December 3rd update, right-clicking a furnace/workbench/chest while holding a lava bucket would leave you with a lava spring on top of the said item, but now it just opens the inventory as it would have if you were carrying, say, a stack of wood.

If you use lava as a fuel in a furnace, going into the nether will cause the burning time to reset to 100 more uses!

Trivia

 * Lava is only called lava once it reaches the surface, and is called magma when underground. As such, most of the 'lava' in Minecraft is actually magma.
 * Lava in a block immediately southwest (diagonally adjacent) of a player or other entity can burn them if they are in the southwest corner of the block they are in. See south-west rule for more information.
 * Lava can be used for creating incinerators to destroy unwanted items.
 * Lava can be contained by surrounding it with snow blocks, because they are not flammable.
 * Lava can be useful as a protection for many buildings, as an example, when building a base, as you can make a moat of lava around the building to protect it against aggressive mobs.
 * An easy way to 'fill-in' large pools of lava is to use gravel or sand, which will fall to the bottom of the pool and stack upwards.
 * An easy way to find lava is to press the "F" key and look for square embers.

Lava Bucket
Lava can be collected through a bucket giving a lava bucket. However only lava springs can be collected. Lava buckets can also be used as fuel for furnaces, giving a far more effective fuel than coal at the expense of the bucket (100 smelts instead of 8).