Obsidian is a unique crafting material created when Water and Lava collide, at which point it forms placed Blocks that can be mined and collected. Obsidian appears as an Ore and is gathered similarly, but has no bar form of its own; though it is required in order to craft Hellstone Bars. Mining Obsidian requires a Nightmare Pickaxe, Deathbringer Pickaxe, Molten Pickaxe, any Drill, or Bombs/Dynamite.
- Obsidian is not destroyed by Lava, despite not being of Blue Rarity.
- Obsidian is fairly rare naturally and will usually require player intervention to spawn.