Java Edition guides/Caves & Cliffs

This guide is a simplified overview of all changes in the Caves & Cliffs updates ( 1.17.x and 1.18.x releases), which assumes at least some familiarity with the Nether Update (Java Edition 1.16.x releases).
== Mobs ==
=== New ===
Axolotl 		
*Lush Caves	
*None	
*Comes in 5 variants.
*Can be picked up in buckets.
*Attacks all fish, squids, guardians, and drowned.
*Gives Regeneration I and removes Mining Fatigue I when the player helps an axolotl kill a mob.
*Bred with a bucket of tropical fish.
*"Plays dead" to regenerate health.
Glow Squid		
*Underground water	
* (when killed by a player or tamed wolf)	
*Glows in the dark, similar to spider and enderman eyes.
*Temporarily loses glow when attacked.
Goat 		
*Mountains (Snowy Slopes, Jagged Peaks, and Frozen Peaks)	
* (when killed by a player or tamed wolf)	
*Jumps higher than other mobs.
*May attack other mobs by ramming them.
*Rarely spawns as a screaming goat, which has a unique set of sounds and a more hostile behavior.
*Bred with wheat.
*Can be milked.
*Runs on its own.
=== Changed ===
Shulker		
* If a shulker is hit by another shulker's projectile, it now has a chance of spawning a new shulker.
Drowned		
* Drops copper ingots instead of gold ingots.
Stray 		
* Skeletons now convert to strays when freezing in powder snow.
== Blocks ==
=== New ===
Amethyst Buds and Cluster 		
*Grows on the sides of budding amethyst.	Can drop loot with hand, but the proper tool is the pickaxe.	
* Used for gathering amethyst shards.
Block of Amethyst 		
* Generates inside of amethyst geodes.	Pickaxe (Iron or better) 	
* Used for decoration.
Budding Amethyst 		
* Generates inside of amethyst geodes. 
* Cannot be obtained.	Pickaxe (drops nothing) 	
* Used to grow Amethyst Clusters.
* Breaks when pushed by pistons.
Calcite 		
* Generates in the middle layer of amethyst geodes.
* Generates in strips in stony peaks biomes.	Pickaxe 	
* Used for decoration.
Smooth Basalt 		
* Generates on the outer layer of amethyst geodes.	Pickaxe 	
* Used for decoration.
Tuff 		
* Generates in patches below Y=0.
* Generates as filler rock in iron ore veins.	Pickaxe 	
* Used for decoration.
Tinted Glass 			Any 	
* Glass that doesn't allow light to pass through.
Copper Ore 		
* Found in the Overworld from Y=0 to Y=96; most common at Y=47-48.	Pickaxe (Stone or better) 	
* Drops raw copper.
Copper Block 			Pickaxe (Stone or better) 	
* Used for decoration.
* Advances to the next stage of Weathering every 50-82 in-game days.
* Can crafted or used with Honeycomb to become waxed, which stops it from weathering.
* Weathering can be reduced with an axe or by a lightning strike.
Cut Copper 			Pickaxe (Stone or better) 	
* Used for decoration.
* Advances to the next stage of Weathering every 50-82 In game days.
* Can crafted or used with Honeycomb to become waxed, which stops it from weathering.
* Weathering can be reduced by an axe or a lightning strike.
Cut Copper Slabs and Stairs 			Pickaxe (Stone or better) 	
* Used for decoration.
* Advances to the next stage of Weathering every 50-82 in-game days.
* Can crafted or used with Honeycomb to become waxed, which stops it from weathering.
* Weathering can be reduced by an axe or a lightning strike.
Lightning Rod 			Pickaxe (Stone or better) 	
* Used to redirect lightning, possibly to avoid fires or for use in farms.
Candle 			Any 	
* Can be used as a light source but it needs to be lit with flint and steel, fire charges, or flaming arrows.
* Extinguish candles using water or by simply right-clicking.
* Can be dyed.
* Can be placed in groups of four.
* Can be placed on top of a cake to make a cake with candle.
Powder Snow 		
*Obtained from cauldrons laid out under snowy weather.
*Generates in groves and snowy slopes.	Bucket 	
* Picked up with a bucket.
* Mobs and players can sink and walk through powder snow, taking freezing damage.
* Leather armor provides immunity to freezing. Leather boots prevent sinking.
* Skeletons buried in powder snow transform into strays.
* Can be placed by dispensers containing powder snow buckets.
* Puts out flames on burning mobs, at the cost of the powder snow block being destroyed.
* Fire mobs (blazes, magma cubes, striders) take more damage from freezing; ice mobs (strays, polar bears, snow golems) and the Wither are immune to freezing.
Dripstone Block 		
* Generates in dripstone cave biomes.
* Generates in dripstone clusters.	Pickaxe 	
* Used for growing pointed dripstone if a water source is above the block.
Pointed Dripstone 		
* Generates in dripstone caves.
* Generates in dripstone clusters.
* Grown from dripping stalactites.
* Sold by wandering traders.	Any 	
* Stalagmites deal damage to any entity that falls or jumps on top of it.
* Stalactites fall when the block above it is broken, dealing damage to any entity it hits.
* Stalactites can drip water, or lava if there is lava above the stalactite. These drops can be picked up by cauldrons, and also allows for renewable lava.
* Can be broken with tridents.
Sculk Sensor 		
*Obtainable only using commands.	Hoe 	
* Detects vibrations made from nearby entities or blocks and emits a redstone signal. 
* Redstone comparators can measure vibration frequencies from sculk sensors and convert them into redstone signals of different strengths.
* Detects only certain things, such as entities walking, flapping wings, or blocks being placed or broken.
* Cannot detect vibrations made behind a block of wool.
Glow Lichen 		
*Generates in caves.	Shears 	
*Produces light.
*Can be spread with bone meal.
Azalea 		
*Generates in lush caves.
*Grows from moss blocks fertilized with bone meal.
*Drops from azalea leaves.	Any 	
*Used for decoration.
*Comes in normal and flowering variants.
*Can be grown into azalea trees.
Azalea Leaves 		
*Generates on azalea trees.	Shears 	
*Used for decoration.
*Comes in normal and flowering variants.
Cave Vines 		
*Generates in lush caves.	Any 	
*Grows glow berries.
*Vines with berries on them produce light.
Big Dripleaf 		
*Generates in lush caves.
*Grows when small dripleaves are bone mealed.	Axe 	
*Can be stood upon.
*Tilts if an entity stands on it for longer than 1 second, causing the entity to fall through.
*Immediately tilts if hit by a projectile.
*A redstone signal prevents it from tilting.
Small Dripleaf 		
*Generates in lush caves.
*Sold by wandering traders.	Shears 	
*Grows into big dripleafs.
*Can be planted only on clay blocks, moss blocks, or while submerged in water.
Hanging Roots 		
*Generates beneath azalea trees.
*Grows from rooted dirt fertilized with bone meal.	Shears 	
*Used for decoration.
Rooted Dirt 		
*Generates beneath azalea trees.
*Sold by wandering traders.	Any 	
*Shearing rooted dirt drops hanging roots and converts it into regular dirt.
*Hanging roots can be grown by applying bone meal.
Moss Block 		
*Generates in lush caves.
*Grows from moss blocks fertilized with bone meal.
*Can be found in shipwreck chests.
*Sold by wandering traders.	Axe 	
*Applying bone meal creates grass, moss carpets, azaleas, and flowering azaleas.
*Applying bone meal converts adjacent stone and sediment-based blocks into moss blocks.
*Prevents saplings placed on it from growing into trees.
Moss Carpet 		
*Generates in lush caves.
*Grows from moss blocks fertilized with bone meal.	Any 	
*Used for decoration.
Spore Blossom 		
*Generates in lush caves.	Any 	
*Produces spore particles.
Deepslate 		
*Generates below Y=8.	Pickaxe 	
*Used for decoration.
Infested Deepslate 		
*Generates when a silverfish infests deepslate.	Pickaxe 	
*Spawns a silverfish when broken.
Cobbled Deepslate 		
*Drops from deepslate.	Pickaxe 	
*Used to craft stone tools, furnaces, and brewing stands.
Polished Deepslate 			Pickaxe 	
*Used for decoration.
Deepslate Bricks andCracked Deepslate Bricks 			Pickaxe 	
*Used for decoration.
Deepslate Tiles andCracked Deepslate Tiles 			Pickaxe 	
*Used for decoration.
Chiseled Deepslate 			Pickaxe 	
*Used for decoration.
Cobbled Deepslate,Polished Deepslate,Deepslate Brick andDeepslate TileSlab, Stairs and Wall			Pickaxe 	
*Used for decoration.
Deepslate Ores 		
*Generates wherever deepslate and tuff generate.	Pickaxe 	
*Function the same as their stone equivalents, but take twice as long to mine.
Blocks of Raw Iron, Copper and Gold 			Pickaxe 	
*Used for storage of raw metals.
Light 		
*Obtainable through commands.	N/A 	
*An invisible, non-solid, waterloggable light source.
*Shows particles indicating its location when held in hand, like the barrier.
=== Changed ===
Cake 		
* Can now have candles placed on them.
Cauldron 		
* Now used to collect dripping liquids from pointed dripstone.
* Can now be filled with lava and powder snow.
Dirt Path 		
* Can now be created from dirt, coarse dirt, podzol, and mycelium.
* Renamed from Grass Path
All Rails 		
* Can now be waterlogged.
All Signs 		
*Have been given new textures.
*Sign text can now be made to glow using glow ink sacs.
*A normal ink sac can be used to remove the glowing effect.
Coal, Diamond, Emerald, Gold, Iron, Lapis Lazuli and Redstone Ore 		
*Have been given new textures for accessibility.
*Iron ore and gold ore now drop raw iron and raw gold respectively instead of themselves.
Blackstone, Polished Blackstone Bricks and Cracked Polished Blackstone Bricks		
*Have been given new textures.
Mossy Cobblestone and Mossy Stone Bricks 		
*Can now be crafted using moss blocks.
== Items ==
=== New ===
Amethyst Shard 		
* Obtained by breaking fully-grown amethyst clusters.	
* Can be used to craft amethyst blocks, spyglasses, and tinted glass.
Copper Ingot 		
* Has a chance to be dropped by drowned.	
* Can be used to craft copper blocks, lightning rods, and spyglass.
Spyglass 			
* When used, the player's view zooms in, allowing them to see distant objects close up.
Powder Snow Bucket 		
* Obtained by using a bucket on a snow cauldron or block of powder snow.	
* Can be used to place powder snow.
Bucket of Axolotl 		
* Obtained by using a water bucket on an axolotl.	
* Can be used to spawn an axolotl.
Glow Ink Sac 		
*Drops from glow squids.	
*Can be used to make sign text glow.
*Can be used to craft glow item frames.
Glow Berries 		
*Grows on cave vines.
*Can be found in mineshaft chests.	
*Produces light while on the vine.
*Can be eaten to restore and 0.4 saturation.
*Can be used to plant cave vines.
*Can be fed to foxes.
Raw Iron, Copper and Gold 		
*Drop from their respective ores.	
*Can be smelted into ingots.
*Can be crafted into compacted blocks.
*Allows iron ore, gold ore, and copper ore to be compatible with the Fortune enchantment.
Music Disc ("otherside") 		
* "otherside" music discs can be found in chests in strongholds and dungeons.	
* Plays the track "otherside" from the Caves & Cliffs soundtrack.
Spawn Eggs for all new mobs		
* Obtained from the creative inventory.	
* Can be used to spawn the corresponding mob.
=== Changed ===
Clock 		
* Has been given a new texture.
Compass and Lodestone Compass 		
* Have been given new textures.
Doors (excluding crimson and warped)		
* Have been given new item textures.
Signs 		
* Have been given new item textures.
Sugar Cane 		
* Has been given a new texture.
== Non-Mob Entities ==
=== New ===
Glow Item Frame				
*An item frame that glows.
== Structures ==
=== New ===
Amethyst geode 		
* Underground	
* No	
* No	
* A round chamber consisting of an amethyst and budding amethyst inner wall, a smooth basalt outer wall, and a layer of calcite in between.
* Comes in many different sizes.
Dripstone Cluster		
* Dripstone Caves	
* No	
* No	
* A large vertical cluster of dripstone blocks.
Azalea Tree 		
* Above Lush Caves
* Grown from azalea and flowering azalea.	
* No	
* No	
* Indicates the location of a lush caves biome.
* Lots of rooted dirt generate below natural azalea trees.
* A tree currently made of azalea leaves and oak logs.
Ore vein 		
*Underground	
*No	
*No	
*A large cluster of long strips of stones and ores.
*Granite and copper ore veins generate above Y level 0.
*Tuff and iron ore veins generate below Y level 0.
=== Changed ===
Mineshaft 		
*Mineshaft pieces no longer generate if they would be fully floating in the air.
*Corridors now generate with oak log or dark oak log pillars or chains for support if needed.
*Cobwebs no longer generate if they would not be connected to solid blocks.
Stronghold		
*Now generate encased in stone, preventing nearby caves from intersecting them.
Fossil 		
*Generates with deepslate diamond ore instead of coal ore when below Y=0.
== Biomes ==
=== New ===
Dripstone Caves		
* Contains lots of dripstone blocks and pointed dripstone on the floor and ceiling.
* There are large columns made of dripstone blocks extending from the ceiling to the floor of the cave.
* Contains many small pools of water.
* Contains larger deposits of copper ore.	
* Amethyst geodes
* Dungeons
* Mineshafts
* Strongholds
Lush Caves 		
* An azalea tree generates on the surface to indicate the biome's location.
* Terrain is covered with lots of moss and clay.
* Many kinds of plants grow in this biome, including grass, vines, dripleaves, azalea, cave vines, and spore blossoms.
* Contains many pools and terraces made of clay and water.	
* Amethyst geodes
* Dungeons
* Mineshafts
* Strongholds
Meadow 		
* A new mountain sub-biome that often generates at the base of mountains.
* Resembles a plains biome with blueish grass and numerous flowers.	
*Birch Trees
*Villages
Grove 		
* A new mountain sub-biome that generates on the slopes of mountains.
* Resembles a snowy taiga biome with a surface made of snow blocks and powder snow.	
*Spruce Trees
Snowy Slopes 		
* A new mountain sub-biome that generates on the slopes of mountains.
* Consists of several layers of snow and powder snow blocks on top of stone.	
Stony Peaks 		
* A mountain sub-biome that generates on the peaks of mountains.
* Usually generates when the surrounding base biomes are too hot for jagged or frozen peaks.
* Has a surface made of stone and strips of calcite.	
Jagged Peaks 		
* A mountain sub-biome that generates on the peaks of mountains.
* More likely to generate as sharp peaks compared to the other peak biomes.
* Has a surface made of stone and snow.	
Frozen Peaks 		
* A mountain sub-biome that generates on the peaks of mountains.
* Tends to generate rounded peaks.
* Has a surface made of snow and packed ice.	
===Changed===
All Biomes		
*Terrain, cave, and biome generation has been completely overhauled.
*The height limit and depth limit have both been increased by 64 blocks.
*There is now natural variation in terrain shape and elevation independently from biomes.
*New mountain biomes and cave biomes have been added.
*Cave biomes generate naturally underground and inside mountains.
*Cave generation has been overhauled to include new types of caves, such as cheese, spaghetti, and noodle caves.
*Local water levels and lava levels in caves can create underground water and lava lakes at different elevations.
*Ore distribution has been overhauled, with each ore now peaking in frequency at a different elevation.
*Large underground ore veins have been added.
*Clouds have been raised to Y level 192.
*There is now much more variation in beach size.
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