End Stone

End Stone also known as Ender Stone is a rare stone like building block found only in the End, its blast resistance is a bout 1.5 times bigger than most stone blocks, and since Endermen can't pick it up, and the Ender Dragon can't break it, this block makes a good material to build shelters in the End with. End Stone also has a similar pattern to Cobblestone, just recoloured.

Unlike Obsidian even though being rare, it is easy to mine, since you can mine it with any pickaxe tier and it can still mine fast. Although in the Survival mode, it is very hard to collect in large quantities since it requires a succesful trip to the End and back, but in 1.3 it has been made slightly easier to get just by dropping an Ender Chest in the End and the Overworld you can safely transport the stone.