Caves & Cliffs

Caves & Cliffs is the name for a major update that will be released for most versions of Minecraft, likely as Java Edition 1.17 and Bedrock Edition 1.17.0. It was announced in Minecraft Live 2020. It will include new cave and mountains features, as well the glow squid, a mob that was voted for during the second Minecraft mob vote.

Planned additions
Please note that the names of many features are conjectural.

Blocks

 * Azalea Leaves.png Blooming Azalea Leaves.png Azalea Leaves
 * Part of a new exclusive tree marking lush caves


 * Azalea Roots.png Azalea Roots
 * Also part of that tree
 * Looks like a colonized dirt block


 * Amethyst geode block.png Amethyst Geode
 * Generates amethyst crystals on top given time
 * Unobtainable in survival, and probably cannot be moved with pistons
 * Extremely rare, only generates in amethyst geode structures


 * Amethyst crystal cross.png Amethyst crystals
 * Grow on top of geode blocks over time
 * Break to produce a crystal shard item
 * These can be crafted into telescopes


 * Copper Ore.png Copper Ore
 * New ore, found underground.
 * Drops itself when broken, like other metal ores.
 * Spawns in new large ore veins.


 * Block of Copper.png Block of Copper
 * Develops a patina of pale green copper carbonate over multiple stages, which might be sped up by weather such as rain.


 * Copper Stairs.png Copper Stairs
 * Develops a patina of pale green copper carbonate over multiple stages, which might be sped up by weather such as rain.


 * Copper Slab.png Copper Slab
 * Develops a patina of pale green copper carbonate over multiple stages, which might be sped up by weather such as rain.


 * Restoring clay pots.png Clay Pots
 * Ceramic Shards can be incorporated into an unfired pot
 * Can be fired by lighting fire under the pot


 * New Vine.png New Vine 2.png Spore plant
 * Light source
 * Grow edible glow berries.


 * Spore Blossom.png Spore Blossom
 * Sends particles downward


 * Dripleaf Plant.png Dripleaf Plant
 * A plant that can be used for platforming
 * If the player stands on top of the plant for a period of time, the player falls through the plant


 * Baby dripleaf plants.png Small dripleaf plant-like blocks
 * Appear highly varied in models


 * Unidentified foliage object.png Unknown foliage block, possibly Moss
 * Looks grassy on all sides and opaque


 * Foliage carpet.png Unknown foliage carpet
 * Same texture as the above unknown block, but one pixel thick


 * Roots bloody roots.png Unknown hanging roots block
 * Seen in the distance of a lush caves biome, behind a spore blossom


 * Baby azalea tree.png Baby blooming azalea tree.png Small versions of azalea trees or azalea bushes
 * May or may not be saplings


 * Sculk Block.png Sculk Block


 * Sculk Something.png Sculk end stone-like block


 * Sculk Growth.png Sculk Growth
 * A layer that generates on top blocks like snow
 * Some have parts are transparent allowing the player to see the block it is on top of


 * Sculk Sensor.png Sculk Sensor
 * Can be used for wireless redstone
 * Senses block placement, footsteps, or projectiles
 * Wool can occlude its ability to sense


 * Stalagmites.png Stalagmite
 * Can be found in the new dripstone caves on the floor
 * Deals damage when fallen on


 * Stalactites.png Stalactite
 * Can be found in the news dripstone caves on the ceiling
 * Can fall, probably damaging entities
 * Can drip water to fill cauldrons


 * Unknown speleothem block.png Unknown block associated with speleothems

(possibly Dripstone, based off of the name of the biome which it is found in)


 * Appears to be made of the same materials as stalactites and stalagmites, but as a full cube.


 * Lightning Rod.png Lightning Rod
 * Crafted with copper
 * Redirects nearby lightning strikes to the top of the rod, which can prevent flammable structures from catching on fire during thunderstorms.


 * Powdered Snow
 * Deceptively similar to snow, but entities fall through it. Likely related to the "snowier snow" announced when the Mountains won the 2019 biome vote.


 * Unidentified Stalagmite Torches.png Candle-like blocks
 * Can be 1, 2, 3, or 4 in a block similar to sea pickles
 * Can be black or white
 * Emit fire particles


 * Unnamed Stone.png Unknown stone

(possibly Marble or Limestone)


 * Can be found around the deep dark cave biome walls
 * Can be found in huge groups

Items

 * Amethyst Shard
 * Drops from Amethyst Crystals
 * Used to make telescopes


 * Axolotl Bucket JE1.png Axolotl Bucket
 * Obtained by using a water bucket on an axolotl, similar to cod, salmon, pufferfish, and tropical fish
 * In demo had no name, showing its translation string "item.minecraft.axolotl_bucket"


 * Brush
 * Used to carefully sweep away debris from archaeological items
 * Removes one pixel of height from the dirt or gravel block it is used upon each use
 * May allow for the creation of dirt and gravel layers and previously unobtainable block heights


 * Bundle
 * Can contain 64 of any item
 * Items are added by dragging bundle to an item
 * Tooltip shows icons of contained items
 * Items drop to inventory when right clicked


 * Ceramic Shards
 * Obtained with brush at archeological sites
 * Come in different colors and different designs, each depicting a different picture, such as an ender dragon, Alex, a skeleton, a tree and a grey skinned humanoid (possibly an Illager)
 * Can be placed/customized on clay pots


 * Glow Berries
 * Can be eaten


 * Telescope
 * Crafted from crystal shards and copper
 * When held, allows the player to see far away in a small circle

Mobs

 * Axolotl.png Axolotl
 * Aquatic creature found in bodies of water within the Lush Caves
 * Can be caught in a bucket like fish
 * Can be tamed by a fish
 * May come in different colors (Albino, yellow, and purple/pink)
 * Plays dead when damaged to regenerate health
 * Attacks drowned, guardians, elder guardians and other fish.


 * Glow squid


 * Originates from Minecraft Earth
 * Glows in the same way that magma cube cores, blazes and the eyes of spiders, drowned and endermen do.
 * Lives in underground lakes.


 * Goat.png Goat


 * Spawns in mountains biomes
 * Can jump very high into the air to avoid obstacles
 * Attacks close animals and knocks them very far away
 * There is a baby variant and therefore presumably a way to breed them


 * Warden.png Warden


 * Spawns deep underground
 * Attacks the player when they sense movement
 * Follows sources of noise such as snowballs hitting blocks
 * Seems to follow the same rules as the skulk blocks when detecting noise
 * Incredibly strong ( of damage)
 * has 85 or more hitpoints
 * at least as fast as a player's walking speed
 * likely spawns in relation to the hut seen in the clip
 * seems to get faster when attacked.

World generation

 * Lush caves


 * Generate below Azalea trees
 * Contain glow berries


 * Mountains
 * Revamped
 * Contain powdered snow and goats


 * Deep Dark
 * New biome at the "deepest depths of the world"
 * Warden is found inside
 * Contains the unidentified stalagmite torches
 * Contains the Sculk block


 * Dripstone caves
 * Contain stalactites and stalagmites


 * Cave generation
 * Revamped to generate bigger, more adventurous caves.


 * Amethyst geode
 * A tiny underground cave-like feature
 * Contains geode blocks and the amethyst crystals they generate
 * Bell-like sounds can be heard here - whether a block emits these or if it's a biome thing (like the exclusive ambience for nether biomes) is unknown


 * Archaeological Excavation
 * New structure with brushes


 * Unnamed Abandoned Underground House
 * Can be found in the deep
 * Contain cobwebs
 * Stripped spruce log support beam runs across ceiling
 * Barrels, a double chest, and a blast furnace are included

Gameplay

 * Archaeology
 * The player can find items and blocks in gravel and dirt by using the brush
 * Possible items:
 * Diamond block
 * Emerald block
 * Ceramic shards of varying color, which depict different images.


 * Dark Flashing
 * While in the deep dark biome, the screen occasionally darkens limiting the player's visibility. This may be the unknown candle like block's light darkening

Minecraft Live 2020
Screenshots of the Caves and Cliffs Update from Minecraft Live 2020: