Oh dang, this one's tough.

Ok so if the top of the bottle is where the top scarf curls around, then I assume it might be slightly tucked under the top of the bottle, creating a verrrry small gap, but just large enough to let oxygen in.

But if the top of the bottle is where the diamond is, then either it's some kinda spell, or the diamond doesn't entirely seal the top of the bottle.

Most of that was assumption/guessing, so I think you win this round. :-P