Lava

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

Natural occurrence
Lava primarily occurs in large magma pools deep underground, on levels 1 through 10. It can also occur as lava rivers from a single spring block, pouring down caves into pools.

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.

A few blocks of lava can also be found in NPC Villages in smithies.

In the Nether, lava is extremely common, appearing as frequently as water in the normal world. Lava also pours from the ceiling. In the nether lava travels 8 blocks like water in the real world.

Burning



 * In 1.9 pre-release lava droplets will fall from the roof of caves if there is a lava block immediately above it. Thus giving a visual warning to the player not to dig that block. This extends to the surface world and has a counterpart effect for water.  The droplets do not harm the player.


 * 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 entity touches water during this time, the fire will be put out.


 * TNT, bookshelves, leaves, wool, fences, wood, planks, and wooden stairs are flammable. If flammable blocks are within 3 meters of lava, they will eventually catch fire. Non-flammable blocks block this effect, but not the spreading of active fire.


 * Contrary to popular belief, the “embers” or “fireballs” which fly out of lava are purely decorative and do not directly cause fires.


 * Lava does not ignite anything below it, just above it and to its sides. This can create interesting structures.


 * Warning: If you are playing on peaceful difficulty, it is still possible to die. The regenerating hearts and loss of hearts from being on fire 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. However, if you stay in the lava itself, you'll lose hearts much more rapidly and die. However if your hunger bar is filled enough to regen, you will survive the burning as long as you are not in the lava.

Flowing
Lava flows far more slowly than Water, and sometimes sourceless lava flows will linger for a very long time. It flows 3 blocks horizontally from its contact point (7 in the nether), vs. water's 7. See Fluids for detailed information on how lava and water flow.

The interaction of lava and water:
 * Since 1.9, if lava flows on top of still or running water, it creates stone.
 * If lava flows horizontally into water, cobblestone is created. Using this you can create cobblestone farms.
 * 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 lava spring is destroyed in the process, so unlike Cobblestone it is not continuous and renewable.
 * If vertically falling water touches still lava on any side Obsidian is created - even if the water would not run into the lava's square.

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, flowers, mushrooms, levers, both types of torches, redstone wire, and rails. Note it doesn't flow over pressure plates, fences, or even wood or wool blocks. Sugar cane holds back lava, but will disappear if the Sugar cane's water source is destroyed by the lava.

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.



As of the 1.9 pre-release, if there is a body of lava flowing above a block, the lava visually seeps down through the host block. This "dripping" effect also applies to Water, although water droplets seep through at a much faster rate. These droplets are purely aesthetic and will not affect the player or other blocks in any way.

Lava Bucket
You can collect and place Lava springs using a Bucket. As with Water, you can only harvest the 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, to light an area, or to create traps. When used to create obsidian, water will be used to cool the lava either before collecting it with a diamond pickaxe in a mold in the desired shape, or by emptying the bucket next to an artificially created waterfall.

Lava can be placed in a furnace in a bucket to be substituted for coal. Its burning time is 1000 seconds, compared to 80 seconds for coal (100 smelts vs. 8). Using a lava bucket as a fuel source consumes both the lava and the bucket, though Notch has hinted this may change in the future.

Lava can also be used as a garbage disposal, by creating a 3×3 box of any unflammable block and leaving a 1 block gap inside. Pour lava into it and drop unwanted items.

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It can also be used as a light by using glass as the wall. It is also a good idea to have a contained water spring next to it, or to carry a bucket of water.

Lava bucket as a weapon
Lava buckets can be some of the most destructive weapons in the player's disposal:

Pros

 * Infinite uses, no durability
 * Large area of effect, depending on terrain
 * Slows down the mobs
 * Also acts as lighting
 * Used as a trap
 * Fast, almost certain kill
 * Player can maintain distance from mob

Cons

 * Just as dangerous to the player, usually deadly if water is not near. To avoid this downside drink a potion of fire resistance.
 * Takes long time to flow
 * Kills slowly, unless the mobs stay in the lava
 * Usually destroys the loot
 * Can take a long time to disappear, potentially blocking your escape route

History




Classic
At first lava had a different texture, but then changed to the current texture. The old texture can still be found in the terrain.png file at the minecraft.jar. 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, and swimming through it causes greater damage. 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 if the player places a sand or gravel block, letting it drop into the lava. If water is let into the area where the Lava is, the lava will form Stone, allowing 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 (7 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. All objects burn instantaneously when dropped into lava. Fired arrows will not disintegrate, but will appear to catch fire and can still be picked up.

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.

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 smelts.

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 can be contained by surrounding it with snow blocks, because they are not flammable and do not melt.
 * 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.
 * 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 nothing.
 * You can see the stars when in lava, even if it's supposed to be translucent.
 * If an item falls into the edge of a lava pool, it may pop back out and appear as is it were burning. Also, you can pick the item back up once it's back on land. More common in SMP.
 * Unlike water, lava does not move the player in the direction it is flowing.
 * Lava falling directly on top of water will make it evaporate instead of forming cobblestone.
 * It is possible to collect an item immediately after it's been ignited by lava, if the player is close enough to it.
 * Lava can spread up to 7 blocks away in the Nether, opposed to 3 normally.
 * In the 1.9 Pre-release, when blocks have lava above them, they have a dripping effect. This also affects water, albeit with a faster effect.
 * In the 1.9 Pre-release, whenever lava flows over water it forms Stone rather than Cobblestone in previous versions (Still forms Cobblestone when water flows over flowing lava).
 * In singleplayer, if a player dies in lava but opens the crafting menu before death, the player will fall over and only the foot of the player will be on fire. Also any skins will revert back to the default skin. This is fixed by closing the crafting menu and respawning.
 * As of Beta 1.8, when lava is touched by rain, it emits smoke (but does not transform into another block).
 * Despite the fact that lava and water create cobblestone and/or obsidian, lava is not affected by rain.
 * Although lava is a liquid, it is not possible to drown in lava. This applies to all mobs.