Hey! So basically, I created a gem system. Included with a upgrade command, tags, reaction based on what level block you are up to and more.
Players start off with emerald ores (right click), then upgrade to diamond then to pumpkin. If you do /gems, there will be a list of admin commands and normal player commands.
If there are any bugs, from game breaking to colour code mistakes, please reply and notify me! Thanks.
Have fun!
Gems Code (pastebin)
Reactions add-on (also pastebin)
Tags add-on + crates add-on (not completed, tell me if you want me to add more tags, and the crate item is an ender chest.)