Obsidean

'Obsidian, (from the Greek root obsidios, meaning unable to be mined without a diamond pickaxe') is a hard black mineral from the game Minecraft. It is created when water and lava fuse, and can only be mined with a diamond pickaxe, the world's strongest device. It cannot be blown up with TNT. Real Minecraft ultimate professional super gamers build their bases from obsidian. It is also necessary to build the Nether portal.