As far as I know there's no limit. But you could be wrong thinking you have enough crystals. Some spells are very expensive to raise to level 3 (Sacrifice 10+20+30= a total of 60 crystals, Turn Back Time 60 crystals,Geyser 60 crystals, Armageddon and Dead Star will take 75 crystals).
See for yourself at
http://forum.1cpublishing.eu/showthread.php?t=12249. Ivra made a nice spelllist (the file is named Spells v2.pdf).