I have received a box of jewelry from my grand mother who just passed away. In the box I found a pearl necklace, but I do not know if it is real or not. Is there a simple test to tell if it is a genuine strand? I showed it to a friend of mine that worked at a jewelry store a few years ago, but she said the only way to tell was by having it x-rayed. I am hoping there is a simple method to tell if it is real, and to find out if it has much value.