How to Get a Heavy Core in Minecraft

Guide Java Bedrock

Quick answer: Open ominous vaults in trial chambers with ominous trial keys: the heavy core is their rarest drop, roughly a 7.5% chance in Java. It's not renewable, not craftable, and its only use is crafting the mace (heavy core + breeze rod).

What you need

Ominous Bottles (Bad Omen)
Strong combat gear for ominous waves
Ominous trial keys (30% from ominous spawners)
1 breeze rod for the mace

Step by step

Gear up for ominous trials: you need ominous trial keys, which come from ominous trial spawners (30% eject chance) - and those only activate while you have the Bad Omen effect from an Ominous Bottle.
Get Bad Omen: drink an Ominous Bottle, dropped by raid captains (pillager outposts, patrols) or found in trial chambers vaults. Walk into a trial chamber with the effect and spawners turn ominous.
Farm ominous keys: ominous spawners summon buffed, armored mobs with potion effects. Complete them and 30% of the time they eject an ominous trial key (plus ominous bottles, keeping the loop going).
Find the ominous vaults: they're the vaults with a glowing-eyed skull, usually tucked in higher rooms and harder spots of the chamber than standard vaults.
Open every one: each ominous vault has roughly a 7.5% chance (Java) to eject a heavy core - expect to open many. Loot is per-player once, so multiplayer groups multiply the odds per vault.
Craft the mace: 1 heavy core + 1 breeze rod. The mace's smash attack deals bonus damage based on your fall distance before the hit - and negates your own fall damage on a successful smash.
Treat it as a trophy block: placed heavy cores are waterloggable decorative blocks, mineable fastest with a pickaxe. In Java they stick to pistons and slime blocks; in Bedrock they can be pushed but not pulled.

Java vs Bedrock

The core difference is the drop chance: ominous vaults yield heavy cores at about 7.5% in Java (Bedrock's rate is similar but its loot table differs slightly). Piston behavior also differs: Java cores stick and pull like normal blocks; Bedrock cores push but won't pull or stick to slime/honey.

Versions: Heavy cores were added as experimental content in Java 1.20.5 and Bedrock 1.20.80, then fully released with 1.21 (Tricky Trials, June 2024).

Frequently asked questions

Where do you get a heavy core?

Only from ominous vaults in trial chambers, opened with ominous trial keys. The chance is roughly 7.5% per vault in Java - it's the rarest item in the structure.

What is the heavy core used for?

One recipe: the mace. Heavy core + breeze rod. The mace deals smash-attack damage scaling with your fall distance and can be repaired with breeze rods.

Is the heavy core renewable?

Not in any practical sense - ominous vaults are one-open-per-player, so each vault is a single shot per person. New trial chambers (and multiplayer friends) are the only way to more chances.

How do you start an ominous trial?

Drink an Ominous Bottle (raid captains drop them, vaults contain them) to get Bad Omen, then approach trial spawners in a trial chamber. They convert to ominous spawners with harder mobs and better loot, including the ominous keys you need.