Gemstone Caverns

If Gemstone Caverns is in your opening hand
and you're not playing first, you may begin the
game with Gemstone Caverns on the battlefield
with a luck counter on it. If you do, exile a card
from your hand.
{t}: Add {c} to your mana pool. If Gemstone
Caverns has a luck counter on it, instead add one
mana of any color to your mana pool.