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Regions Unexplored adds 5 specialized cave biomes that transform underground exploration with glowing plants, crystal formations, massive mushrooms, and volcanic activity.

Cave biome features

Underground biomes appear naturally during world generation beneath the surface, each with distinctive visual effects and resources.

Unique vegetation

Each cave biome features exclusive plants that only grow underground, from glowing mushrooms to aquatic flora.

Ambient particles

Atmospheric particle effects create immersive environments, from prismatic sparkles to volcanic ash.

Custom lighting

Bioluminescent plants and crystal formations provide natural light sources in the darkness.

Specialized resources

Gather unique materials found nowhere else, including prismarite clusters and mineral formations.

Lush cave variants

These underground biomes feature water, vegetation, and vibrant ecosystems.
A lush underground delta featuring ancient aquatic vegetation and mineral-rich pools. The water glows with an otherworldly cyan color, and the foliage displays deep green tones with purple grass accents.Temperature: 1.125 (warm) | Precipitation: Yes

Features

  • Mineral pools with unique geological formations
  • Bladed grass providing ground coverage
  • Corpse flowers - rare and unusual plants
  • Duskmelons - edible underground crops
  • Dusktrap plants - carnivorous vegetation
  • Dropleaf plants near water
  • Clay deposits for building materials

Atmosphere

  • Water color: Cyan (-13369345)
  • Foliage: Deep green (-10118056)
  • Grass: Purple tinted (16318340)
  • Music: Lush caves ambient

Mobs

Spawns axolotls, tropical fish, and standard peaceful mobs. Safe for exploration with aquatic wildlife.
Massive underground mushroom forests featuring giant bioshroms in vibrant blue, green, and pink colors. Creates an alien landscape with bioluminescent fungal growth.Temperature: 1.25 (very warm) | Precipitation: Yes

Features

  • Giant green bioshroms - massive mushroom trees
  • Giant blue bioshroms - towering fungal structures
  • Cave grass and tall cave grass coverage
  • Blue, green, and pink bioshroom varieties
  • Unique fungal ecosystem

Atmosphere

  • Water color: Standard blue
  • Foliage: Deep green (-11093361)
  • Grass: Dark green (-11093410)
  • Music: Lush caves ambient

Mobs

Spawns axolotls, tropical fish, and peaceful creatures. The fungal environment supports unique wildlife.
Bioshroms are exclusive to this biome and provide unique decorative blocks when harvested.

Dry cave variants

Dangerous underground biomes with unique geological features.
A crystalline underground chasm filled with prismarite formations that sparkle with magical particles. Features purple-tinted vegetation and glowing crystal clusters.Temperature: 0.925 (cool) | Precipitation: Yes

Features

  • Prismarite clusters - valuable crystal formations
  • Hanging prismarite - ceiling-mounted crystals
  • Prismoss sprouts with purple coloration
  • Cave hyssop flowering plants
  • Ambient prismarite sparkle particles

Atmosphere

  • Water color: Standard blue
  • Foliage: Deep purple (-16737793)
  • Grass: Purple tinted (-6625354)
  • Particles: Prismarite sparkles (0.001 density)
  • Music: Dripstone caves ambient

Mobs

Standard hostile cave mobs including zombies, skeletons, and creepers. Exercise caution while mining crystals.
Prismachasm is one of the rarest cave biomes. Mark coordinates when you find one to return for prismarite farming.
Underground caverns naturally rich in redstone with pointed redstone formations growing from floors and ceilings. The entire biome has a reddish tint.Temperature: 0.8 (cool) | Precipitation: Yes

Features

  • Pointed redstone - natural redstone stalactites and stalagmites
  • Enhanced redstone ore generation
  • Reddish foliage and grass
  • Standard cave features with redstone theme

Atmosphere

  • Water color: Standard blue
  • Foliage: Dark red (-6044317)
  • Grass: Dark red (-6044317)
  • Music: Dripstone caves ambient

Mobs

Standard hostile cave spawns. The abundant redstone makes this biome valuable for technical builds.
Redstone caves provide excellent redstone farming opportunities. Set up mining outposts to harvest the abundant ore.
Volcanic underground caverns with active lava flows, basalt formations, and ash particles. The hottest and most dangerous cave biome.Temperature: 2.0 (scorching) | Precipitation: No

Features

  • Overworld lava deltas - extensive lava pools
  • Basalt blobs - natural basalt formations
  • Ash vents - volcanic activity
  • Lava falls - dramatic flowing lava
  • White ash particle effects

Atmosphere

  • Water color: Standard blue (rare)
  • Foliage: Dark ash (-8949914)
  • Grass: Burnt color (-8621472)
  • Particles: White ash (0.1 density)
  • Music: Deep dark ambient

Mobs

Standard hostile mobs spawn despite the heat. Fire resistance recommended for exploration.
Bring fire resistance potions when exploring scorching caves. Lava is abundant and dangerous.

Locating cave biomes

1

Use locate command

Use /locatebiome regions_unexplored:biome_name to find specific cave biomes. Note that cave biomes may be far from spawn.
2

Explore below Y=0

Cave biomes generate in deepslate layers. Explore underground cave systems below Y-level 0 for the best chance of discovery.
3

Look for visual cues

Unique particle effects, lighting, and vegetation colors indicate you’ve entered a special cave biome.
4

Mark coordinates

Cave biomes can be rare. Always mark coordinates when you find one for future resource gathering.

Mining strategies

Harvest unique aquatic plants and mineral pools. Bring water breathing potions for extended exploration. Axolotls can be captured for breeding.
Cave biomes can overlap with vanilla cave types like dripstone and lush caves, creating hybrid areas with features from both.

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