Beginning of Game

[Vindog]

say I have a  {Serum Powder} In hand and i also have a  {Gemstone Caverns} In hand. Can I put then caverns in then use the powder for 6 new cards?

[Sardok]

From the rulings of {Gemstone Caverns}:

6/1/2011   Your "opening hand" is the hand of cards you decide to start the game with after taking any mulligans.

So, you would first mulligan your hand with {Serum Powder}, then put {Gemstone Caverns} on the battlefield if it is in your opening hand after mulligans.

[Vindog]

Ok thanks