Can you bring a diamond ring on the plane?

Your concern regarding a diamond ring should be a concern for its safe keeping. You are best advised to wear it. If you can't wear it, you can secure it within your intimate clothing, either in a jewelry bag and a stitch or two to secure it to your underwear.

Transporting a diamond ring in your carry-on bag, or your purse or briefcase, or checking it as luggage makes it easy to lose track of.