Mox Aquamarine

{t}, Remove all Charge counters from Mox Aquamarine: Add an amount of mana in any combination of {g} or {u} equal to the number of
Charge counters removed in this fashion.
Charge - Discard an artifact card
(At the beginning of your upkeep, you may exile an artifact card from your hand and tap this permanent
to put X+1 Charge counters on it where X is the
number of Charge counters on it already.)