They looked like they were a couple of carats each. If they were a good quality and high C ratings (as only EJ would purchase) it’s possible. Improbable but possible.
I don’t know about her but my diamond earrings, which are WAY smaller, have a screw on back so you can’t lose them. Very awkward to get on but worth the peace of mind.
I thought it was pretty ridiculous for her to be on her hands and knees throwing the sand around looking for it. Sure, cover it up instead of finding it.