Tutorials/Block and item duplication

This page seeks to teach you how to clone items and blocks without building a separate farm for them, in vanilla Survival mode. It can be treated as an "everything farm," since it can "farm" things that can't normally be farmed, like diamonds and dragon eggs.

Note that these techniques are considered "cheating" by many people and Mojang tries to remove the ability to duplicate in Survival at almost every update. On some servers, these techniques are ban-able offenses.

The best way to duplicate a block is to turn it into an item first, then duplicate the item. But, there are other ways to duplicate the blocks themselves, though they only work for certain blocks. Shulker boxes make item duplication much easier because they allow for up to 1,729 items to be cloned at once (including the shulker box).

Why Bother?
Duplicating items and blocks can be very useful. For example, let's say you wanted to obtain enormous amounts of glass or sand. Going into a desert and mining it yourself is extremely time-consuming, so a sand duplicator can be very useful.

If you wanted to break a lot of bedrock using this technique, the player can build a dragon egg duplicator to create more dragon eggs.

Hopper Method
This is by far the most common and the simplest way to duplicate.

1. Place two hoppers facing into each other.

2. Put the item you want to duplicate in one of the hoppers, so the item is moving back and forth between the hoppers.

3. Unload the chunks and reload them. This can be achieved by walking away, going to a different dimension, etc.

4. Repeat step 3 until the item is duplicated. It could take a few tries.

The way it works is that when the chunks containing the hoppers is reloaded in the middle of a hopper transferring the item, both hoppers "think" that they both contain that item that was transferred. This causes the item to appear in both hoppers. The player can emphasize this effect by adding more of these hopper duos nearby and making the hoppers transfer their items into different chunks.

Deadly Method
This method is extremely deadly, but not necessarily to the player. This method involves taking a mob that can carry items (such as a zombie, donkey, or llama) down to a very low health, as in a half of a heart or less. Using extremely precise timing, kill that mob as it travels through an end portal. The items equipped and the mob should appear in the other dimension. It works by tricking the game into thinking the mob is alive on one end of the portal and dead on the other side. The live mob travels through the portal still carrying the items, and the dead mob's items are also sent into the portal, allowing the player at the other end to collect the cloned items and the mob carrying them.

Block Duplication
Although there is no one machine able to clone every block in their physical form, there are certain types of blocks that can be cloned.

Rail Duplication
This can be accomplished by moving the rail in such a way that it moves into an invalid location and breaks, but then moves back to a valid location before it could break. Minecraft cannot react to the changes fast enough, so it creates one rail item out of thin air and leaves the physical rail in the new valid location.

TNT Duplication
TNT duplication works in a similar way as rail duplication. A physical TNT is BUD-powered, so when it finally realizes it has been powered, it ignites, but partway through the change from a block to an entity, it is quickly moved out of the way. This confuses the game, so it leaves a BUD-powered unlit TNT block in its new location and creates a TNT entity out of thin air, which falls and explodes just like if it was actual TNT.

Gravity Block Duplication
There are many ways to do this, but the basic idea is the same.

A gravity-affected block is pushed toward an end portal. It becomes an entity as it falls into the portal, and it travels into the other dimension's "spawn point." But, before it's removed from the original dimension, it bounces off an entity in the portal (in a vehicle so it won't go through), and is caught by some pistons. It then turns into a block and is returned to its original location. This process can be looped using redstone. It works for any block that is affected by gravity, except for primed TNT because it would blow up the contraption.

Dirt Duplication
Dirt duplication relies on the crafting recipe for coarse dirt. Coarse dirt is crafted with 2 dirt blocks and the player gets 4 coarse dirt from it. If the player hoes the coarse dirt, it becomes normal dirt. Some of this new dirt created can go into crafting more coarse dirt. You can continue this process infinitely, as long as you built a gravel duplicator using the method above.