Be able to combine like crystals

[Seto Kaiba]

I had this idea to have crystals other than just key making so the idea is;

in the charge screen you can take a crystal of the same type of the one you are charging and it gains the charges & the current charge(and maybe the shades mix?)

[SP1D3RP1G]

this would be cool. Maybe just so it isnt as OP have them only keep like 80% of the sum of the charges.