Netherrack

Netherrack (formerly known as Netherstone ) is a rock-like block found in the Nether.

Obtaining
Netherrack can only be collected with a pickaxe.

Natural generation
Netherrack makes up most of the Nether's terrain.

In Pocket Edition, Netherrack is created when a Nether Reactor is activated.

Usage
When netherrack's top is lit on fire, it burns infinitely.

Trivia

 * Netherrack can be destroyed by hand in 2 seconds, making it the stone which can be destroyed in the least amount of time.
 * Netherrack can be mined in 50 milliseconds with a golden pickaxe (or a diamond pickaxe enchanted with any level of efficiency). However, there is a .25 second delay between mining blocks.
 * In the game code, it is referenced as "hellrock".