Crystals

[Nahald]

So one thing that's kind of been bothering me for quite some time now is the crystals that are obtained during the course of the main quest in 2.0. Mostly my issue is that I cannot seem to recall where exactly you find the crystals, the circumstances under which they are obtained and, ultimately, what purpose they serve. This has been bothering me especially since they seem to reappear every now and then in the later parts of the story, like when you see them surround your character before defeating Lahabrea or when your character produces one of the crystals when they confront Ramuh.

So I was wondering if perhaps anyone here could recall where exactly all of the crystals are obtained from over the course of the story. Details including where they are obtained and under what circumstances they are obtained would also be appreciated. Although I suppose if you could remember the quests they are all obtained on, that'd be helpful because I could then just watch the cutscenes for those quests. And a refresher on what purpose the crystals serve would also be helpful if possible. As I said before, none of the wikis seem to have any sort of comprehensive information on the crystals that your character obtains throughout the course of the main story. I'm hoping I can post any information that I can get on the Final Fantasy Wiki, at the very least. Any help would be appreciated.^^