diff --git a/src/main/java/ru/betterend/registry/StructureRegistry.java b/src/main/java/ru/betterend/registry/StructureRegistry.java
index 6a9cb13b..219b489d 100644
--- a/src/main/java/ru/betterend/registry/StructureRegistry.java
+++ b/src/main/java/ru/betterend/registry/StructureRegistry.java
@@ -27,7 +27,7 @@ public class StructureRegistry {
 	
 	public static final EndStructureFeature GIANT_MOSSY_GLOWSHROOM = new EndStructureFeature("giant_mossy_glowshroom", new StructureGiantMossyGlowshroom(), Feature.SURFACE_STRUCTURES, 16, 8);
 	public static final EndStructureFeature MEGALAKE = new EndStructureFeature("megalake", new StructureMegaLake(), Feature.RAW_GENERATION, 4, 1);
-	public static final EndStructureFeature MOUNTAINS = new EndStructureFeature("mountains", new StructureMountain(), Feature.RAW_GENERATION, 3, 2);
+	public static final EndStructureFeature MOUNTAIN = new EndStructureFeature("mountain", new StructureMountain(), Feature.RAW_GENERATION, 3, 2);
 	
 	public static void register() {}
 	
@@ -38,7 +38,7 @@ public class StructureRegistry {
 	public static void registerBiomeStructures(Identifier id, Biome biome, Collection<Supplier<ConfiguredStructureFeature<?, ?>>> structures) {
 		if (id.getNamespace().equals("minecraft")) {
 			if (id.getPath().equals("end_highlands")) {
-				addStructure(MOUNTAINS, structures);
+				addStructure(MOUNTAIN, structures);
 			}
 		}
 	}
diff --git a/src/main/java/ru/betterend/util/sdf/operator/SDFRotation.java b/src/main/java/ru/betterend/util/sdf/operator/SDFRotation.java
index 8bc580ab..3452c255 100644
--- a/src/main/java/ru/betterend/util/sdf/operator/SDFRotation.java
+++ b/src/main/java/ru/betterend/util/sdf/operator/SDFRotation.java
@@ -7,7 +7,8 @@ public class SDFRotation extends SDFUnary {
 	private static final Vector3f POS = new Vector3f();
 	private Quaternion rotation;
 	
-	public SDFRotation setRotation() {
+	public SDFRotation setRotation(Vector3f axis, float rotationAngle) {
+		rotation = new Quaternion(axis, rotationAngle, false);
 		return this;
 	}
 	
diff --git a/src/main/java/ru/betterend/util/sdf/primitive/SDFHexPrism.java b/src/main/java/ru/betterend/util/sdf/primitive/SDFHexPrism.java
new file mode 100644
index 00000000..c2df5d0e
--- /dev/null
+++ b/src/main/java/ru/betterend/util/sdf/primitive/SDFHexPrism.java
@@ -0,0 +1,26 @@
+package ru.betterend.util.sdf.primitive;
+
+import ru.betterend.util.MHelper;
+
+public class SDFHexPrism extends SDFPrimitive {
+	private float radius;
+	private float height;
+	
+	public SDFHexPrism setRadius(float radius) {
+		this.radius = radius;
+		return this;
+	}
+	
+	public SDFHexPrism setHeight(float height) {
+		this.height = height;
+		return this;
+	}
+
+	@Override
+	public float getDistance(float x, float y, float z) {
+		float px = Math.abs(x);
+		float py = Math.abs(y);
+		float pz = Math.abs(z);
+		return MHelper.max(py - height, MHelper.max((px * 0.866025F + pz * 0.5F), pz) - radius);
+	}
+}
diff --git a/src/main/java/ru/betterend/world/features/RoundCave.java b/src/main/java/ru/betterend/world/features/RoundCave.java
index 3f16656c..ceee05c7 100644
--- a/src/main/java/ru/betterend/world/features/RoundCave.java
+++ b/src/main/java/ru/betterend/world/features/RoundCave.java
@@ -2,6 +2,7 @@ package ru.betterend.world.features;
 
 import java.util.Random;
 
+import net.minecraft.client.util.math.Vector3f;
 import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.math.BlockPos.Mutable;
 import net.minecraft.world.Heightmap;
@@ -9,9 +10,14 @@ import net.minecraft.world.StructureWorldAccess;
 import net.minecraft.world.gen.chunk.ChunkGenerator;
 import net.minecraft.world.gen.feature.DefaultFeatureConfig;
 import ru.betterend.noise.OpenSimplexNoise;
+import ru.betterend.registry.BlockRegistry;
 import ru.betterend.registry.BlockTagRegistry;
+import ru.betterend.registry.StructureRegistry;
 import ru.betterend.util.BlocksHelper;
 import ru.betterend.util.MHelper;
+import ru.betterend.util.sdf.SDF;
+import ru.betterend.util.sdf.operator.SDFRotation;
+import ru.betterend.util.sdf.primitive.SDFHexPrism;
 
 public class RoundCave extends DefaultFeature {
 	@Override
@@ -61,6 +67,22 @@ public class RoundCave extends DefaultFeature {
 			}
 		}
 		
+		if (random.nextBoolean() && world.getBiome(pos).getGenerationSettings().hasStructureFeature(StructureRegistry.MOUNTAIN.getStructure())) {
+			pos = pos.add(random.nextGaussian() * 5, random.nextGaussian() * 5, random.nextGaussian() * 5);
+			BlockPos down = pos.down(BlocksHelper.downRay(world, pos, 64) + 2);
+			if (world.getBlockState(down).isIn(BlockTagRegistry.GEN_TERRAIN)) {
+				SDF prism = new SDFHexPrism().setHeight(radius * MHelper.randRange(0.6F, 0.75F, random)).setRadius(3).setBlock(BlockRegistry.AURORA_CRYSTAL);
+				float angleY = MHelper.randRange(0, MHelper.PI2, random);
+				float vx = (float) Math.sin(angleY);
+				float vz = (float) Math.sin(angleY);
+				prism = new SDFRotation().setRotation(new Vector3f(vx, 0, vz), random.nextFloat()).setSource(prism);
+				prism.setReplaceFunction((state) -> {
+					return state.getMaterial().isReplaceable() || state.isIn(BlockTagRegistry.GEN_TERRAIN);
+				});
+				prism.fillRecursive(world, pos);
+			}
+		}
+		
 		return true;
 	}
 }