Sometimes, people tended to lose their urge to imagine something when things were really beyond imagination. In the eyes of the mages, the huge magical crystal might be some sort of Magical Crystalloid or something else, but definitely not a magical crystal.
"What we have to do is actually the same as usual. We just have to stay here to meditate and accumulate mana. There are books on magic that President brought back from the Haiga Mountain Range on that bookshelf. Those books are the teaching material for magic that the High Elves used during the Dark Age. If you have any doubts during this period of time, you may read the books to find the answers to your questions. If you can't find any answer, President will give you the answers…" Gavin instructed, after which he picked a few mages and sat down with them to meditate.