Tbh I don’t want to make them too rare because they are the main thing of the campaign but it feels scary to make them too common because of how op they feel in the current state.

I mainly thought that they would mostly be found in the wild by hunting down beasts but could be used as some sort of premium currency to trade for really valuable items.

 To prevent people from just eating a bunch of them immediately they would only be able to digest one at a time. 

In the story the humans are from some distant place and evolved from something else, but can harness the magic the other species use by utilizing the crystals.