Do Eren's crystalization powers come from the Attack Titan or from the Founding Titan? In episode 50 of the Attack on Titan anime, Eren blocks one of the wall holes with his crystalizations powers. Do Eren's crystalization powers come from the Attack Titan or from the Founding Titan?
Eren can use the abilities of the founding titan only when he's in contact with someone among the royal bloodline. Thus all abilities Eren uses during combat is from the attack titan.

This was confirmed when Erin encounters the titan that ate his mother in season 2 episode titled "Scream", he was able to control all the other titans with his scream as he touched her.
That was the only time till date Eren was able to use the founding titans abilities.