THESE ARE USUALLY AFGHANISTAN MADE CARNELIAN / AGATE SEALS OR ...The seals can be of two types: talismanic, and therefore aimed exclusively at the protection of the wearer, or functional, used to seal letters and dispatches, imprinting them in hot wax.
If they are seals they are normally cut in reverse. They are nice worn around the neck usually on a silver chain thus the loops on the back. They are found in all the souks over there and in places like Sharjah or Muttrah ...but loads can be seen in Kabul ...The famous Chicken Street souk being crammed with such charms...