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Ore regions

Every ore you break is stamped with the biome it came from. 72 regions, and the stamp survives smelting, compaction and the trip to the bank.

The stamp, and what is in it

When you break an ore block, the server does not let the vanilla drop through. It cancels it, reads the biome you are standing in, and drops its own replacement carrying a hidden data tag plus one extra lore line naming the region. That tag is the origin stamp, and it is the reason two iron ingots that look identical can forge into different tools.

The stamp is a seven-field record: the biome key, a material modifier name, four numbers (durability bonus, weight modifier, heat resistance bonus, flexibility bonus) and the lore tag. There is no rarity field and no random component anywhere in it. The same biome always produces the same stamp, byte for byte.

The region table holds 72 regions. 57 are keyed to Terralith biomes, the remaining 15 to vanilla biomes: plains, stony peaks, jagged peaks, swamp, mangrove swamp, deep dark, dripstone caves, the four Nether biomes, soul sand valley and the three End biomes. Any biome with no entry of its own resolves to the plains fallback, whose four numbers are all zero. Mining in an unlisted biome therefore gives you metal with a stamp that changes nothing.

The four numbers that reach the forge

Only the four doubles drive forged stats. The biome key, the modifier name and the lore tag are identity and decoration: they tell you and the server which region this is, and they never touch a stat. When you forge with stamped metal, those four values are read out of the tag and folded into the finished item.

Across the whole table the values sit in these bands: durability bonus -0.05 to +0.18, weight modifier -0.22 to +0.20, heat resistance bonus -0.05 to +0.35, flexibility bonus -0.08 to +0.22. Regions are grouped under 17 modifier names, the most common being mountain_durable (12 regions), balanced (8) and lush_flexible (7).

The trade-offs are deliberate. Volcanic metal is the most heat resistant in the game and pays for it in flexibility. Skylands metal is the lightest by a wide margin and slightly less durable than plain. Glacial metal is the toughest and mildly poor at holding heat.

An honest limit: more than 30 of the 72 rows carry at least one value that is clamped away by the code that reads it, usually because a negative number is discarded where only a positive one has an effect. Those regions still differ from plains on their other values, but not every configured number in the table is doing work.

What the stamp survives

A stamp that only lasted until the first furnace would be worthless, since almost nothing is forged from raw ore. The stamp is therefore carried through smelting and through the vanilla compaction recipes, so the region you mined in is still readable in the ingot, in the block you stored it as, and in the netherite ingot at the end of the chain.

The craft listener drives the result slot rather than the produced items, which is what makes shift-click bulk crafting behave: every item produced comes out stamped, the counts stay right and nothing duplicates.

Two limits are worth knowing before you build around them. A furnace tracks one profile at a time, taken from its most recent input, so feeding one furnace mixed regions will mis-attribute or drop the stamp rather than track each item; feeding it unstamped ore clears the entry outright, which errs toward a plain ingot instead of a wrong biome. And when a crafting grid holds several regions at once, the merge keeps a single winner (ranked by total bonus magnitude, then by how often it appears, then by grid position) and the minority regions are gone for good on that round trip.

The 29-material allowlist

The stamp is only ever written onto one of 29 materials. Anything else is left completely untouched. The list is deliberately narrower than the set of things that could technically carry a tag, because a stamp on the wrong item is not a feature, it is a stack that will not merge.

What is kept off the list matters as much as what is on it:

• Ore blocks themselves. A Silk Touch pickaxe gives you a plain diamond ore block that stacks with every other one. Regions attach to what comes out of the rock, not to the rock.
• Glowstone dust and echo shards. These are bonus loot from two biome groups and have nothing to do with forging. They used to be stamped, which quietly split them into unstackable piles. They now drop clean.
• Quartz blocks and amethyst. Decorative or not reversible back into a stamped input.

The rule is simple to hold in your head: if a material is not on the list, the writer does nothing at all, so a stamp can never appear on a hopper, a tool, a dye or a piece of glowstone.

Why identical stamps stack, and a full stack smelts through

Minecraft merges two items only when their data is exactly equal. Any difference at all, down to a single character in a lore line, splits the stack. Two things make that work here.

First, the stored tag is built by concatenation in a fixed key order. There is no map iteration, no timestamp, no unique id and no random value, so the same region always produces the same string. Second, the visible lore line is rendered from the region's own name in that same string, not from the biome you happened to be standing in. That second point fixed a real bug: two biomes sharing one region used to print different biome names and refuse to stack, even though their forging stats were identical.

The result is that a piece of iron mined in Sakura Grove and a piece mined in Sakura Valley behave exactly as their profiles say, and any two items with the same profile merge into one stack.

Player extraction depends on a server call that can decline in rare cases. When it does, the failure is in the safe direction: you get a plain, unstamped ingot. It never duplicates and never re-introduces the one-item cap.

Terralith biome groups and their bonus drops

On top of the stat profile, twelve biome groups grant a bonus drop when you break ore inside them. These only fire when Terralith is present, they roll per ore break, and they sit on top of the normal drop rather than replacing any of it.

The last column follows the allowlist and nothing else. Amethyst shards, dyes, magma cream, glowstone dust and echo shards are not forging materials, so they drop plain and stack with the ones you already have. Quartz, diamonds, emeralds, gold and the raw metals are, so they arrive stamped with the same region as the ore you were breaking.

Bonus drops used to carry their own flavour labels, lines like "Volcanic Flux" and "Glacial Crystal". Those are gone. The reason is stacking: a labelled bonus quartz would not merge with a normally mined quartz from the same region, and one inventory slot per drop source is a worse deal than a bit of flavour text is worth.

The Lush and Cloud Forest bonus is the odd one out and the most valuable of the twelve at depth, because it copies whatever you just mined. A diamond break there has an 18% chance of a second diamond, stamped identically, landing in the same stack.

Fortune, Silk Touch and the single drop authority

Because the ore system cancels the vanilla drop and produces its own, it has to reproduce vanilla's enchantment behaviour exactly, or every pickaxe on the server would quietly lose its enchantments' effect on ore. It does this by asking the game for the drops your held tool would have produced, then stamping those. Fortune levels and Silk Touch are therefore weighted correctly, including on Bedrock.

• Vanilla Fortune passes straight through. The tool in your hand is what the drop calculation is given.
• Silk Touch gives you the ore block, which is not on the allowlist, so it comes out plain and stacks with any other. Break it later and the drop is stamped with wherever you broke it, not where you mined it.
• The forged Precision Pick adds bonus Fortune on top of whatever the tool already has. Its level is the item's quality tier divided by two. That bonus is folded into the same single drop calculation, so its extra ore is stamped along with the rest instead of arriving as an unstamped second pile.
• The Ore Fortune and double-drop buffs stamp their duplicates through the same resolver, so a duplicate is byte-identical to the original and merges with it.

The mining skill tree has one node built on top of this. Region Lore is a tier-2 mining node that gives a 35% chance of one extra raw ore per break in a biome that has an ore region of its own. It sits behind the same prerequisite as Rich Seam, which is the flat 20% version that works anywhere.

Banked bullion keeps its region

Metal you stamp into bullion at a bank keeps its origin. A bar batch is identified by the issuing bank, the mint day and the region, so a Sakura gold bar and a Volcanic gold bar are two different bars and will not merge. When you redeem a bar, the metal that comes back carries a stamp byte-identical to freshly mined metal of that region, and the two stack together.

This was a deliberate reversal of an earlier decision, and the cost is named rather than hidden: more stacks and more inventory pressure. If you mine in four regions you now carry four gold-bar stacks where you used to carry one. The non-merging is the point of the feature, not a side effect of it.

Three practical consequences:

• Old bars are not broken. A bar minted before regions existed carries no region key, is read as generic, and still stacks with new plain bars. Nothing you already hold was split or invalidated.
• Blocks and nuggets are stripped on the way in. Only the four smelted ingots and seven base drops of the same tier are priced individually by region. A stamped diamond block would be priced as a plain block but decompacts into nine individually priced stamped diamonds, so the bank removes the stamp from anything outside that set as it enters stock, and tells you at the moment it happens. Raw ores keep their stamp: they are what carries the region into the furnace in the first place.
• A retired region does not eat your metal. If a region is later removed from the table while your metal is banked, the metal comes back plain. Units are never lost, only the provenance.

Known edges

Everything above is written from the code. Much of it is recent and marked code-written and reviewed, not server-verified, which means it has been read and argued over but not yet proven on a live server. If something here does not match what you see in game, the page is what is wrong.

The edges worth knowing:

• Region Lore fires in plains. The check that asks whether a biome has a region of its own compares two objects rather than two names, and the plains region is loaded twice under slightly different identities. The node therefore answers yes everywhere, which makes it a strictly better Rich Seam. This is a known defect, flagged and not yet corrected because correcting it is a balance change.
• One profile per furnace. Mixed regions in a single furnace will not be tracked per item. The system errs toward dropping the stamp rather than attributing a wrong biome.
• Compaction is lossy when mixed. A block crafted from ingots of several regions keeps one and loses the rest permanently.
• A furnace destroyed by an explosion can hold a stale pending profile until a furnace placed at the same coordinates smelts again and overwrites it.
• Not every configured number does something. More than 30 rows carry at least one value that its reader clamps away.

None of these can duplicate items or lose the metal itself. Every failure path in the system ends in a plain, unstamped stack rather than a wrong or a free one.