Tiny air bubbles!

[ChateauPoisson]

Hi everyone! We have been cycling our tank (10 Gallon) for awhile now, and have recently bought a hermit crab. Lately, one of the rocks has been getting this slight orange tint to it, while the other is purple and green. Now, we've noticed tiny little air bubbles trapped on the rocks, and at the top. Is this supposed to happen? We are such newbies, we want to make sure everything is going well before we start adding to the tank.