costume or real

by joy

My mom passed away a few months ago and I'm trying to help my dad with her things. There is a lot jewelry. Three armoires and we do not know what is real and what is costume. My dad was in the army for thirty years so it is from all over the world. Unfortunately we do not have a trustworthy jeweler in our small town. Can you please suggest the best way of identifying the real pieces? What is a valuable antique costume piece? Thank you for any help you can provide.

Sincerely Overwhelmed