PLEASE READ BEFORE DOWNLOADING THE PLUGIN:
This plugin might seem good at first glance, but it's full of issues that are breaking the database and making all the currencies along with their data being reset after some time/usage.
If you constantly have users earning currency (or even buying stuff with it) aka having their values change, after some time you can literally join and make it reset for everybody.
Have been trying to figure this out for over a month when I had this issue until I decided to pay a developer out of my pocket to fix this (github commits attached below)
I also reported it to the developer a few months ago, and I was told that a update was going to be pushed eventually (surprise! it's still haven't been pushed).
Fixed plugin version:
https://github.com/Gadsee/GemsEconomy/commit/34843b8c105e091bd67612fc917ffce3205cc501
https://github.com/Gadsee/GemsEconomy/commit/1334940237bf6c5750922dd2250b193dfd87b67e