Lava

Lava is a dangerous fluid that follows similar rules to Water. When a source block of Lava is placed, it will flow downwards or outwards, though the number of blocks it will flow outward is not static, and is instead calculated based on the distance the lava has to fall from its source to the nearest solid block.

Lava that comes into contact with a flammable entity or block will set it on fire; lava that comes into contact with an item will destroy that item.

Lava source blocks can be collected in a Bucket or similar container, which will slowly drain the flowing lava. Because Lava does not create an infinite source, it is possible to drain a large lake of Lava using only Buckets, though this is not recommended.

When Lava and Water come into contact, they can produce either Cobblestone or Obsidian, depending on whether source or flowing blocks are touching. Used in this manner, Lava can create a Cobblestone generator, used to produce an infinite source of Cobblestone.