Conductivity

Conductivity is a property of blocks that determines whether redstone signals can be conducted through them, meaning that redstone components are able to power other components touching another side of this block, though it also has a wide range of other effects on the game world.

Conductivity is usually determined by whether a block has a solid-blocking material and a collision box that takes up a full cube, with 5 exceptions:
 * Mud and Soul Sand are conductive, despite having non-full collision boxes.
 * Redstone Blocks, Observers and Pistons are all non-conductive.

Properties
A lot of the effects of conductivity are non-obvious. Minecraft does not have a "solid" property for blocks, so conductivity is tested when a test for "solidity" would normally occur.


 * Redstone behavior (see also: Redstone circuit and its subpages):
 * Only conductive blocks can be powered by power components or transmission components (see list of redstone components).
 * Conductive blocks overhead can prevent redstone wires from connecting to other redstone wire diagonally upwards (and vice-versa for the wire connecting downwards).
 * If a non-conductive block can support redstone wire, it acts as a diode, carrying power upward but not downward.
 * Mobs cannot spawn inside conductive blocks. Conductive blocks also play a part in the pack spawning algorithm.
 * Chests cannot be opened if there is an conductive block on top of them. They are not affected by non-conductive blocks.
 * Ghast fireball explosions start fires only on conductive blocks.
 * Bats cannot hang on non-conductive blocks.