Why i can't learn nature's blessing

hi i am lv 50 elf.
i already chose water line.
problem is even i learned water lifer and nature’s touch. but i can’t learn nature’s blessing crystal.
i clicked the crystal at the mother tree and went again ivory tower… but i couldn’t learn that spell.

Are you using nature’s blessing crystal? or a crystal called natures blessing magnet (non working)

You can learn spells and crystals anywhere on this server.