TNT

TNT acts like a normal block in Creative. However, in Survival it behaves like the Creeper's explosion. Upon being struck by the player, it will start smoking and flashing white. If there are no blocks to hold up the TNT block, activating it will make it affected by gravity and it will fall. After 3-4 seconds, it explodes, destroying a vast amount of blocks, mobs that are nearby, and even the player if they are not careful.

Removing TNT can be tricky, and varies by game. In Survival Test, hitting it two times will stop the countdown and cause the TNT to revert into a resource block which can be picked up. In Alpha and Beta, there is no way to pick up TNT after it has been placed, but it can still be safely removed from the world by placing water atop the TNT, thus immersing it in water. Once it has been completely immersed in water, detonate the TNT.

TNT can clear water and lava. Setting TNT on fire activates it after a while. However, if the TNT falls in water, the explosion will not destroy any blocks at all but still cause damage.

TNT will damage surrounding blocks depending on what blocks are directly touching it or not. Empty space will create a larger destructive radius, while a TNT block completely surrounded by rock will destroy an exact 3x3x3 cube from its center.

This trick can be used to mine out long 3x3x3 hallways without using your valuable pickaxe, though the Sulphur used to make the TNT is probably more valuable.

Since the Redstone update, TNT monster traps can now be created and used successfully, making TNT a valuable resource and a powerful defense. When exposed to a current, the TNT activates as if it had been activated by a player. Combine this with a Pressure Plate and you can create an automatic defense for your buildings (Although a one-time-use, as the TNT needs to be replaced).

For the TNT to receive the circuits signal, the redstone needs to be directed straight into it from at least one of four sides, from either the Layer the TNT is based on, or above or below one layer. Diagonally adjacent entry will not make a connection. Finally, Redstone running alongside TNT will also not work due to existing limitations, as it will not branch out into 'T' or 'X' junctions to connect successfully.

Mining
TNT mining is faster than mining by hand, but drops fewer resources. Of the blocks which are blown up by TNT, 70% (on average) will be destroyed and cannot be picked up.

Trivia

 * A TNT will not explode instantly when hit by a TNT explosion, instead it will be activated and pushed away by the blast. This can be used to create TNT Cannons.


 * Arrows attached to TNT will fall off when activated. This can be used to create arrow cannons.


 * A player or mob sitting in a minecart will take minimal damage from TNT, even when right next to the TNT. This can be used to make people/mob cannons.


 * When TNT is active, objects can go through the block; like water, mobs, and the player. This principle is also used for TNT Cannons.


 * Sand and Gravel blocks will react accordingly to a detonation, scattering from the point of origin.


 * The crafting recipe for TNT references the manufacture of Dynamite (an explosive often confused with TNT), which is made by stabilizing Nitroglycerin with an absorbent material such as sawdust or earth.

Explosion Resistance
These numbers, taken straight out of the code, are the temporary health used during an explosion. The higher the number, the more resistance the block has. Each check on the block decreases the number by an amount determined by the size of the explosion. Once that number reaches 0, the block is destroyed. The damage done by TNT to this temporary health stacks, and it is possible to destroy obsidian given enough TNT. The temporary health resets, presumably when the game sees no more explosions.

The TNT Resistance values listed on each block page are how many of that block a single TNT will destroy in any one direction from the face of the TNT.

TNT