Caverns (also known as Caves) are common underground structures that generate in the Overworld and, to a lesser extent, The Nether. They can generate at any altitude up to y=129, and may span from the surface all the way to Bedrock at y=5. Caverns can consist of randomly generated patches of air blocks and lava source blocks (at y=10 and below), exposing different types of stones and ore veins.
Depending on their elevation, caverns can contain any type of Ore Vein. However, ore is mostly found in larger caverns. Hostile mobs often spawn in caverns which can make them dangerous places to explore if one is unprepared.
Small Caverns, or Caves, are usually found close to the surface. Due to their proximity to the surface, only Coal Ore and sometimes, Iron Ore can be commonly found in them, while other Ore is rarely found.
Medium Caverns are usually twice the size of small caverns. They form deeper underground, and they usually contain more types of ore than their smaller counterparts. Most medium caverns are guaranteed of containing both coal ore and iron ore.
Large Caverns are rarer than the other types of caverns, and they can be found deep underground. They can contain all types of ore. They usually contain large, circular rooms, or long, wide, tunnel-like ravines. They may also intersect Abandoned Mine Shafts or other caves. They can be spread in-between multiple Biomes, and they can (and often) contain multiple entrances.
Open-top Caverns, or Ravines, are tall, thin caves with the distinguishing feature of having an opening to the surface at the top which basically makes them ravines with caves underneath them. Not all ravines are exposed to the surface.
Tunnels (also known as Catacombs) are caverns that connect two or more entrances. They seldom contain ore, and they are shorter and smaller than the small caverns. Usually, on the x and z-axis in the game, tunnels are diagonally positioned.
Hillside Depressions are common caverns that feature a small, naturally generated hole on the side of a steep slope or cliff-face, usually found in the Extreme Hills Biome. They are much smaller than either small caverns or tunnels, and as a result they rarely contain ore, and can only contain up to only coal ore.
- Larger caverns usually have an abundance of ore. Remember to bring the materials to build multiple pickaxes or bring more than two.
- After mining out all the ore in a catacomb, try to "cut" it off by using a transparent block (such as Fences). If ambience is still heard or mobs are still spawning, there may be a section that wasn't explored yet.
- Alternately, if one decides to make use of the naturally-generated cavern as a base, torches can be used to illuminate the cave and prevent hostile mobs from spawning.
- Carry extra torches, greater than one stack. One never knows how big a cavern is.
- Wear at least Iron armor, even on peaceful, due to the dangers of lava. The Feather-falling enchantment will also help.
- Bring at least one bucket of water. This can make retrieving ore (such as Diamond) over Lava much easier, and it will make cavern exploration safer, in general.
- A player can get lost rather easily in caverns. Leaving markers, such as torches, is a good way to prevent this.
- As caverns can often branch off in many different directions, it is a good tactic to place torches on only the left (or right) side of the cavern wall.
- "Refining" the shape of the caves encountered can help prevent a player from getting lost since they will look less random.
- Keep the inventory as empty as possible since it will allow a player to mine more resources with fewer drop-off trips.
- Hostile Mobs are numerous in caverns, so always have a Sword ready - preferably a Stone sword or better.
- To an extent, one can use Creepers in caves to help find more ore as their explosion may reveal a hidden pocket. However, it is dangerous and armor may be necessary.
- Wood is hard to come by in caverns (unless one finds an abandoned mineshaft). Make sure to pack plenty of it before exploring.
- Bring milk in case an abandoned mineshaft is encountered. There are almost always Cave Spiders lurking inside these structures.
- Bring a lot of food! Starving to death in a cavern and losing all of the collected minerals isn't the best way to go.
- If a player is mining Obsidian, make sure there isn't lava under it to prevent either losing the block or falling into the lava.
- Bring or use cheap blocks (such as Dirt) to make bridges across lava pools, gaps, or ravines.
- Always exercise caution when exploring a cavern, especially ravines, as a player is prone to falling to their death through a gap in the floor.
- Caves are generated after ore. As a result, the ore pockets found in caves may not be as big as the ones found while strip-mining.
- On rare occasions, a cavern may have two different entrances in two different types of biomes.
- Jungle caverns may have vines growing in them.
- In the Minecraft Classic version, it's almost impossible to dig straight down without finding a cavern.
- An exciting way to find caves in Minecraft Classic is to find a body of water, and look for holes in a cliff. Explore these, and it is almost positive that there are either an underwater cavern inside, or a player might swim through a tunnel and surface in some sort of cavern.
- Another tip for not getting lost in caves is to always place torches on the left (or right) wall. That way, finding the way out is as simple as making sure the torches are on the opposite side that a player placed them on.
- It is possible, but extremely rare, for a large cave to appear at the surface of the map, leaving a giant crater in the ground.
- If a player is very desperate for food due to a low hunger bar and an absence of animals, a cave can be useful. Zombies spawn in caves, and they drop Rotten Flesh, which can be used to fill the hunger bar. However, this is not advised because a low hunger bar means no health regeneration, and a hungry player can be quickly overcome by a zombie horde. Also, rotten flesh has an 80% chance of causing the Food Poisoning status effect. This can aggravate the problem of starvation instead of helping it.