This is a new ore. You can mine it under 30 blocks.
If you place it down and you active it with redstone it wll spawn 1 TNT, that will explode. Few seconds later the Ultimate TN...
To craft your Ultimate TNT, you will need 5 Ultimate Iron Ingot, 2 Gunpowder and 2 Cactus green dye
The Ultimate TNT needs this ingot to craft it. If you smelt the Ultimate Iron Ore you will get this ingot.