Greetings.
I am a man in a suit who has fallen into the world of Minecraft.
To duplicate an allay, play a music disc in a jukebox and give an amethyst shard to an allay that is dancing.
One allay becomes two.
You do not need a pair of allays for breeding.
You need an allay, a jukebox, a music disc, and an amethyst shard.
After duplication, there is a five-minute cooldown before that allay can duplicate again.
This guide covers Java Edition 1.21.11, separating the official steps from what happens in our OjiCra music hall.
Prepare a jukebox and an amethyst shard

A jukebox sits at the center of the music hall.
Use the block that plays a music disc, rather than a note block.
It makes a fitting centerpiece for my little stage.

There is purple amethyst in the small room.
The item you give to duplicate an allay is an amethyst shard, not this block.
Read the item name in your inventory and select the shard.
It is also useful to choose somewhere you can watch the allay without it flying far away.
The music-hall building itself is not required for duplication.
Play music and give a shard to a dancing allay

I look down at the jukebox after inserting a music disc.
One allay is visible on the left.
In this episode, I play music here and watch the allays.
The official Minecraft instructions explain that allays dance to a music disc playing in a jukebox.
Using an amethyst shard on a dancing allay duplicates that individual.
Use the shard on the dancing allay itself, rather than simply dropping it nearby.

A musical note rises from the jukebox, with allays flying around it.
In our music hall, I give shards to separate allays, taking the total from ten to twelve.
It is a livelier gathering, and simply watching them is enjoyable.
The screenshot shows companions near the stage.
Twelve is the total after duplication, not a claim that every allay appears together in this image.
The official Java 1.19.1 release notes specify a five-minute duplication cooldown.
Java 1.21.11 also sets the cooldown for both the original allay and the newly created one.
The new allay is not a shortcut to duplicating again immediately.
If duplication fails, check dancing, the item and the cooldown
First check that the jukebox is actually playing music and that the target allay is dancing.
Then check that you selected an amethyst shard and are not trying to duplicate the same individual again too soon.
We try this near the stage in OjiCra, but that position is not a universal promise of success within a particular block distance.
Our result also does not establish restrictions by disc type, song duration, or a guaranteed time for an entire group to double.

I bow with the flying companions above and behind me.
Watch one allay dance, use the shard, and then give it time after duplication.
A calm pace suits this old man rather better than rushing!
- QDo I need two allays?
- ADuplication starts with one allay. It is not a breeding procedure that requires a pair.
- QCan I use an amethyst block?
- AThe official procedure uses an amethyst shard. Read the inventory item name so you do not confuse the block with the shard.
- QCan I duplicate an allay with a note block?
- AThis duplication procedure uses a jukebox containing a music disc. It is separate from bringing collected items to a note block.
- QDoes the newly created allay need to wait five minutes too?
- AJava 1.21.11 applies a cooldown to both the original and the new allay. Check the music and dancing, and avoid repeated attempts on the same individual.
Read about building the hall and increasing the group from ten to twelve in Episode 83, the allay music hall.
For more practical guides, visit the Minecraft Memo collection.
Sources: Minecraft: Allay / Java Edition 1.19.1 release notes / Java Edition 1.21.11
That is all for this time.
Greetings.