Block properties

Block properties control how different block types interact with various gameplay mechanics. While some block behaviors are specific to individual block types, such as the ability to open a chest or activate a lever, block properties specify how blocks behave in response to interactions that can occur with any block. For example, fire may attempt to spread to any nearby block, in which case the flammable block property is used to determine if the spread succeeds. Similarly, a piston may attempt to push any block, and the push reaction block property is used to determine if the push succeeds, fails, or destroys the block.

For the most part, block properties are really properties of block types, not properties of individual blocks. For example, if a given block is flammable, all blocks of the same type will be as well. However, the values of some block properties can vary depending on the given block state—for example, fence gates are collidable when closed, but not when open.

The legacy solid block property, usually just called solid, determines if a block is considered "solid" for a number of game mechanics. It is distinct from many other notions of solidity, such as whether the block is opaque, conductive, collidable, is a full block, or allows mob spawning. A slight variant of the legacy solid property is known as blocks motion for historical reasons, though it is also unrelated to whether or not a block is collidable.