At the beginning of the game, when your going through the tutorial, you will get a +100 water attack gem to equip to your infinity blade. As soon as you get the chance take it off of the infinity blade. You only lose $8,000 out of the $250,000 you start with, so live with it. Once you finished the tutorial and you have started your rebirth, the awesome gem will be sitting in your inventory. Once you get the chance, equip it, and you will always have a +100 attack gem with you.

NOTE: You could sell the gem and make a lot of money, BUT i have been playing the game for a very long time and beat the game a numerous amount of times, but the best i have is a +99 shock gem. I know, only 1 difference, but it took FOREVER to find and costed a lot of money. So your keeping it. I hope you like it! :)