18k star sapphire order pendant

Product Name: 18k star sapphire order pendant
I know almost nothing about this. It was my grandmothers. Maybe it was order her moms before that ? It is stamped 18k and it tests positive for 14k. I can't test for 18k because I don't have that one. Any questions please ask and I will try and find out from my mom. The star dances with the light. You can't see the star when their is no light. It's a high dome shape stone. Not flat. I've done many google image searches and have never found this pendant anyplace else's ever. Which leads me to believe it was a custom piece. NOTE- around the outer edges of the stone their are some chips missing. You can't notice when you wear it but if you inspect you'll see them. OPEN TO OFFERS. Also I'm shipping this FedEx due to the high value. I pay shipping.