My necklace my grandmother found buried in a basement

A beautiful necklace that my grandmother found around forty years ago in her old house, it was buried in the basement. I have tried to find information about it but haven't had any luck so I thought that I'd post it for everybody to see. You can't tell but the top stone is like a dark amethyst, when you hold the necklace up to a light the light shines through both stones. This necklace has no makers mark and I am almost positive that it was meant to go on another chain instead of the one that it is on. Regardless it is such a beautiful necklace and I am so glad to have it. As soon as I have it appraised and find out more information about it, I will post an updated.