To be honest, during the MSQ, Garuda forces the captive Amalj'aa and Kobolds to summon Ifrit and Titan, and no crystal was seen there (and even if there were some, they would have probably been drained of their powers by Garuda).
So in my opinion, crystals aren't needed to summon a Primal and sustain its physical form, but they are used to empower the Primal. Without them, the Primal would be weaker, but still able to survive, probably sustaining itself by draining the aether from around them.
So in my opinion, crystals aren't needed to summon a Primal and sustain its physical form, but they are used to empower the Primal. Without them, the Primal would be weaker, but still able to survive, probably sustaining itself by draining the aether from around them.
