Obsidian is a dark, high-resistance block found naturally in all dimensions and formed when water flows over a lava source. It is highly blast-resistant, making it immune to most explosions. It can only be mined with a diamond or netherite pickaxe and is commonly used for crafting and building nether portal frames.

Obsidian generates in structures such as ruined portals, bastion remnants, and woodland mansions. It also forms naturally in the End as part of Obsidian pillars and end ship structures. Additionally, it can be obtained from piglin bartering or generated through interactions between water and lava.

Obsidian is widely used for building explosion-resistant structures and crafting items like enchanting tables, beacons, and ender chests. It cannot be moved by pistons and produces a bass drum sound when placed under a note block.