Nether X adds many new purposes to netherrack. There is still the vanilla smelting it into nether bricks, but now there are a few crafting recipes. It can now be made into tools, a sword, a furnace, and chiseled netherrack. The tools and sword follow the respectable crafting recipes and are the equivalent to stone. Unlike the other tool sets and swords that the mod adds, the netherrack set doesn't have any special abilities. However, it can be execrated in the execration table to give the tools "haste". Click here for chiseled netherrack. Click here for nether furnace.