The jewelry in the AKIN Collection, with sand between sapphire glass, is water resilient but NOT waterproof.
If you forget to remove the jewelry before contact with water, water may enter into the lockets.
If water gets in the sand will get damp, and a mist can form between the glass. It can take quite some time for the water to evaporate out of the locket and the sand to dry but with time it will. You need only wait.