i think yes because usually when u purchase a vancleef piece especially alhambra they give u a card with care instructions , one of the instructions is not use it in water. From my personal experience i used to wear my malachite bracelet all the time even while i shower , after a while the stone lost its shine and got darker
YES.
VCA is fine jewelry and should not be worn to the beach..the salt and water will ruin your piece.
Exception would be the all yellow gold and even then I wouldn't risk it.