, : Double the amount of each type of unspent mana you have.
12/1/2004 Doubling Cube’s ability is a mana ability.
12/1/2004 The “type” of mana is its color, or lack thereof (if the mana is colorless).
12/1/2004 Any restrictions on the mana in your mana pool aren’t copied. For example, if you have with no restrictions on it in your mana pool and that can be used only to cast artifact spells, you’ll end up with , that can be used only to cast artifact spells, and that can be used for anything.