For 50-55 (genkai 1) you will need to get a Bomb Coal, Exoray Mold, and an Ancient Papyrus, then give them to Maat @ Ru'Lude Gardens.

Then to go from 55-60 (genkai 2), Maat will ask you to retrieve Round Frigicite, Square Frigicite, and Triangular Frigicite.

Please look forward to it.