Hello,
I think, it could be a Turkish eye or Nazar. I just found in the internet a very similar piece.
"A nazar or evil eye stone (Turkish: nazar boncuÄŸu) is an amulet that is meant to protect against the evil eye. It is most common in Turkey, Armenia, Iran and Greece. In Turkey it is ubiquitous in offices and homes, in jewellery, including for babies, on vehicles, doors, horses and even cell phones" (Wikipedia).
Kind regards,
Ringo
