How to Fix Ores That Aren't Spawning After Editing JSON

If your edited ore stops appearing entirely, the cause is almost always a JSON syntax error or a bad block name. The library silently skips files it cannot parse, so a single stray comma can disable a whole file.

Check the JSON syntax

Open the file in a text editor with bracket matching or paste it into a JSON validator. Common mistakes include a trailing comma after the last item in an array or object, missing quotation marks around keys and string values, and unbalanced [ ] or { }. Every key such as block, size, and frequency must be in double quotes, and every value that is text (like the block name) must also be quoted. Numbers must not be quoted.

Check the block name and dimension

Confirm the block value is a valid registry name, including the namespace, for example minecraft:coal_ore. A typo means the entry is ignored. Also confirm the dimension value matches where you are looking — an ore assigned to the Nether will never show up in the Overworld.

Test in new chunks

Ores only generate as new chunks load. After fixing the file, reload the game and travel to terrain you have never visited. If it still fails, temporarily reduce your file to a single simple ore entry to isolate which object is broken, then add the rest back one at a time.