Obsidian

Obsidian is a mountain resource found as dark, glassy boulder-like deposits on the slopes of Mountain biomes. It appears more often on higher ground, and the deposits can be broken with an Iron Pickaxe or better. Because the rock shatters when struck, it is best mined from the lower side so fewer shards are lost during extraction.

Obsidian can also be found in loot chests inside Frost Caves, which are likewise located in Mountain biomes. Unlike metals and metal ores, Obsidian can be carried through portals, making it much easier to transport than most late-game mining materials.

It is a key crafting ingredient for several mountain-tier items:

• Obsidian Arrow x20: Wood x8, Obsidian x4, Feathers x2
• Poison Arrow x20: Wood x8, Obsidian x4, Feathers x2, Ooze x2
• Frost Arrow x20: Wood x8, Obsidian x4, Feathers x2, Freeze Gland x1
• Tool Shelf: Iron x4, Finewood x10, Obsidian x4

Because Obsidian is used in both ammunition and crafting station upgrades, it is worth gathering whenever you are exploring Mountains. A single trip up the slopes can provide enough material to support ranged combat, especially if you are relying on arrows for safer fights against Mountain enemies. If you are building or expanding your workshop, keep an eye out for the extra four pieces needed for the Tool shelf as well.

When mining deposits, approach carefully: the pieces are small and can be awkward to harvest if you strike from above or from the wrong angle. Working from the downhill side reduces the chance of losing usable fragments as the deposit breaks apart. If you do not want to mine in the open, Frost Caves offer another source, though availability there depends on finding the right chests.