It's truly sad and a shame that many of us try to "hide" what we are due to anti-Semitic feelings. However, I do understand your concern. It would be a heartbreak if something happened to this precious Chai (or to you, personally). I would opt to either wear a longer chain to conceal it or leave it on-board in your safe, to wear once you are back on the ship.

I've recently begun to take good costume jewelry on trips, rather than chance precious items possibly getting lost or stolen. Just my personal preference.