Xp Gems can be mined with an Iron pickaxe and are found below level 67. (They also spawn in the Nether)
You gain 28 experience points for breaking the block and each gem can be consumed for another 7 Xp each. You can craft them into 3 bottles o' enchanting giving you an average of a 300% increased Xp Drop. Or you can craft them into the experience apple which is a 625% Xp Increase from just consuming the gem itself.
I did my best to balance this mod with survival and not overwhelming. It should help with any Xp grinds you have.
Gem Ore = 28 Xp
Gems = 7 Xp
Bottles = 3-11 Xp
Experience Apple = 350 Xp
Level 30 = 1,395 Xp
This mod was made using MCCreator
https://mcreator.net/eula-legacy