The Underground Dimension

Entering the Underground

You enter the Underground using the elevator near Ignia Market Square. The elevator is located at (x -1500; z 1300) in the Overworld, but its location in the Underground is not fixed. Make sure to note where you enter, so you can find your way back!

The elevator runs on a simple schedule and makes a round trip every 10 minutes. At times where the minutes on the clock are divisible by 10, the elevator goes down to the Underground. At times where the minutes are divisible by 5 but not by 10, the elevator goes up to the Overworld. In other words, it departs every five minutes, alternating direction each time.

Biomes

The Underground has 14 biomes.

Plain biomes

Plain biomes tile across the entire dimension at all depths. They share the same ores and features but differ in how many caves they contain:

• Underground is the default biome with a normal density of caves.
• Solid Rock is a variant that is almost entirely solid stone.
• Grand Caverns is a variant with enormous open spaces.

Core biomes

Core biomes are found in the deepest, hottest regions of the dimension. Ash and lava particles fill the air and visibility is progressively reduced:

• Scorched Caverns are hot caves with lava pools, dripstone formations, hot springs, and blackstone. Only gold, diamond, emerald, and redstone ore generate here.
• Solid Core is a layer of obsidian with no caves and no ores that always separates the Molten Core from the Scorched Caverns.
• Molten Core is the deepest biome, a solid mass of lava with no caves and no ores.

Cold biomes

Cold biomes are found in shallow, humid, cold regions. Strays spawn in both:

• Frozen Caverns have floors and walls of ice, packed ice, and blue ice. Icicles and dense glow lichen decorate the caves.
• Rime Caverns are a transitional cold biome with crystalline rime formations on floors and ceilings, alongside icicles and dense glow lichen.

Arid biomes

Arid biomes are found in shallow, dry regions. Husks and parched spawn in the first two:

• Arid Caverns have sand and sandstone surfaces with cactus. Desert ruins can generate here.
• Red Arid Caverns have red sand and red sandstone surfaces with dead bushes.
• Painted Depths is a terracotta biome with coloured banding similar to badlands. No mobs spawn here.

Other biomes

• Wet Caverns are filled with water pools, dense dripstone clusters, and water springs. Copper ore generates at double the normal rate. Drowned, glow squid, and various fish spawn here.
• Lush Clay Beds are underground gardens with cave vines, spore blossom, rooted azalea trees, clay deposits, and classic vines. Frogs spawn here.
• Infested Caverns are covered in cobwebs with mushrooms and dense glow lichen. Infested ore generates in addition to the standard set. Spiders and cave spiders spawn here.

Structures

• Mineshafts generate in most biomes and contain ore vaults with loot specific to different ore types. Charged silk touch pickaxes can be found in treasure barrels.
• Monster Rooms generate in most biomes and contain high-value loot including totems of undying, enchanted books, and charged silk touch pickaxes.
• Spider Nests generate exclusively in Infested Caverns.
• Desert Ruins generate exclusively in Arid Caverns and contain suspicious sand.

Ore spawning

All standard Overworld ores generate in the Underground. All ores are more common than in the Overworld and spawn equally across all Y levels, with two exceptions: diamond is significantly more common at greater depths, and lapis is more common at low depths. Unlike the Overworld, emerald ore spawns in most biomes rather than being restricted to mountain biomes. More ore is visible on cave walls, making exploration-based mining much more effective than strip mining.