Sylvan Scrying does nothing when both you and your opponent are the same color. Pretty harsh for a card that costs 8 mana to be useless against 1/5 of your opponents.
Maybe it could change some random gems to your color instead?
And Natural Connection is so much better as a common. 3 mana for 3 gems, even if random, will always benefit the player vs all planeswalkers.
I was thinking that it would always try to convert 5 gems, but if it ran out, or found that it was converting gems from one color to the same color, then it would make up the surplus with random gems.