Netherrack

Hellstone (aka Bloodstone, Netherstone, Red Mossy Cobblestone, Brimstone) is a stone that is found only in the The Nether. It burns indefinitely, so it is a good way to have everlasting light. It also has an extremely low resistance to TNT, and can be mined with as little as a stone pick with one hit. The dark red of the stone, along with its abundance in The Nether give it a very chilling ambiance, and also make the region seem darker than it is. Hellstone can be 'lit' with a Flint and Steel and the fire will burn indefinitely, creating a good light source. Hellstone also give off a small amount of light estimated to be the same as the nightime lumination from the moonlight. It is never completly dark in hell even on blocks far away from light sources. It is used purely for aesthetics as of Alpha version 1.20_01, as it lacks any kind of recipe, however it can be used as an alternative to coal or wood to fuel a furnace. Fish, and possibly other items, cannot be cooked with hellstone. Whenever it lasts forever or not in a furnace is unknown.