Which earth sub power do you think would do better in a fight? Sand or crystals?
With sand Manipulation, you'll be able to control the desity a pressure,making it as heavy as a rock. You can create devastating sandstorms and quicksands that can tear the flesh from your enemie's bones, as well as make your battle field crumble into sand and drain the moisture out of any living thing. However, if coming in contacted with water or blood, the sand hardens and becomes breakable.
With crystal manipulation you can control any form of rare gemstones and shape them into weapons or projectiles. You use them to make sheilds to defend yourself from lasers and reflective them. Create sharps pillars and impale your forces from the inside. However, it may vary if the gem is fragile and weak, and it can be shattered by high sound frequencies.
Personally, I like the power of sand. But I want to see what you all think.