Everything has a value.
EternalExchange is an equivalent-exchange alchemy mod for Minecraft 1.21.1 on Fabric. When your world loads, items get EMC values based on their recipes. Learn an item once, break matter down into EMC, and make anything you've learned.
Every item has a price
EMC — Energy-Matter Covalence — is the mod's common currency. It isn't a hand-written list: when a world loads, EternalExchange works through the whole recipe graph and prices what it finds. A vanilla game ends up with about 1,500 values, and mods that add recipes are priced automatically.
Learning is permanent. Put an item in the Transmutation Table (or the portable Tablet) once, and you can make it back for its EMC price forever.
These seven are real values from a fresh world, no other mods installed:
How it works
Learn
Put any item in the Transmutation Table — it's recorded permanently.
Burn
Break matter down into EMC. One piece of coal is worth 128.
Transmute
Spend EMC on anything you've learned — whenever you can afford it.
What's in the mod
Automation
Energy Collectors (MK1–3) make EMC from light. Antimatter Relays (MK1–3) buffer and boost it. Energy Condensers turn raw EMC into copies of whatever you lock inside — set a target and let it run.
Progression
Dark Matter and Red Matter are the expensive materials the endgame is built from — 139,264 and 466,944 EMC. The progression climbs through them: tools, weapons, and armor with charge levels and modes, matter furnaces, and pedestals with ambient powers.
Equipment
Gem armor gives you flight, damage absorption, and offensive abilities on keybinds. There are creative-flight rings, infinite water and lava amulets, and a Philosopher's Stone that transmutes blocks in place — with a live preview before you commit. Klein Stars carry EMC, color-coded 104-slot Alchemical Bags go where you go, and Alchemical Chests hold the rest.
Yours to change
Every value can be overridden with a custom_emc.json, a datapack, or the TOML config. If a mod adds recipes, its items get priced with no patches needed.
{
"entries": {
"minecraft:diamond": { "emc": 8192 }
}
}Screenshots
The mod just launched — real screenshots are on the way. These frames are reserved for them.
Install
- Install Fabric. Run the Fabric Loader installer for Minecraft 1.21.1.
- Download the mod. Grab the latest jar from GitHub Releases.
- Drop it in
mods/. Put the EternalExchange jar and Fabric API in your mods folder. On a server, the same two jars go in the server'smodsfolder.
You'll need: Minecraft 1.21.1 · Fabric Loader · Fabric API · Java 21
Questions
Does it work in multiplayer?
Yes. EternalExchange runs on clients and dedicated servers — install the same jars on both sides.
Does it work with other mods?
Generally, yes. Values are computed from the recipe graph when the world loads, so mods that add recipes get priced automatically. Anything the solver can't reach can be given a value by hand with custom_emc.json.
Is this ProjectE?
EternalExchange derives from the MIT-licensed ProjectE and began as a Fabric port of it. It's developed independently — not affiliated with, maintained by, or endorsed by the ProjectE team. Please report issues on the EternalExchange tracker, not upstream.
Can I change the values?
All of them — override any item with custom_emc.json, ship conversion files in a datapack, or tune the rest in the TOML config.