Giftstone of the DeJaaran

Whenever a spell or ability would cause you to
spend life or spend mana, you may instead choose
whether to spend that much life or spend that
much mana.
If at any time your Life total falls below 10,
remove Giftstone of the DeJaaran from the game.
Held sacred by its people, the cosmic Giftstone
would only bestow its power upon those who were
worthy of it.