I can't tell the difference between the real thing verses cubic zirconia, rhinestones, etc. I have a lot of old jewelry to price - some to sell & some to keep and pass down as family heirlooms. Besides stones, I cannot tell the difference between genuine pearls and fake ones. I also have a hard time telling genuine silver & gold apart from other metals. Some of the pieces have makers marks and in those cases, I can usually find out what I have. Unfortunately, most of my pieces are not marked. Any help would be very much appreciated!