Details of Cubes' Effects on Spells

  Spell       Cubes that increase chance of success

  BLORPLE     (always works)
  FROTZ       Change, Light (75% base chance)
  GNUSTO      Change, Earth (75% base chance)
  LESOCH      Air, Fire
  MALYON      Fire, Life
  REZROV      Change, Earth
  YOMIN       Mind, Light
  SNAVIG      Change, Dark
  GIRGOL      (special, as spell is so powerful)
  LISKON      Change, Earth
  TINSOT      Water, Fire
  JINDAK      Light, Connectivity
  ESPNIS      Mind, Death
  CASKLY      Change, Connectivity
  THROCK      Life, Water

If you have the cube that BLORPLEs you to the Magic Room, it gives an extra-strong power boost to all spells. With this cube in your possession, only the GIRGOL spell can ever fail under normal circumstances. When I use a spell on a scroll, the scroll disappears and I can't use the spell again. Help!

You should GNUSTO the spell into your spell book.
Then you can memorize the spell from your book and use it repeatedly.