Why must gemstones breath?

Question

the holes are in the back of the ring so the gems can breath ......WHY ?????

Answer 1

The holes are there to let light through to make them sparkle more.  Gems don't need to breath.  It just makes them look better.

Answer 2

Otherwise they would suffocate.

Answer 3

Probably so that condensation doesn't form on the stones due to their proximity to the skin.  If there was condensation on them it would foul up the optical properties and they wouldn't shine.