A gorgonite bar is a bar of refined Gorgonite ore. It can be created through the Smithing skill by using gorgonite ore on a furnace, requiring level 80 Smithing and granting 57.4 Smithing experience. The gorgonite ore itself can be mined from the rocks scattered throughout the dungeon, obtained as a monster drop, or bought from the Smuggler.
A gorgonite bar can be smithed on an anvil through the Smithing skill to create Gorgonite equipment, granting between 82 and 86.5 Smithing experience per bar used. A list of gorgonite items that can be smithed from gorgonite bars and the Smithing levels required can be found here.