Ancient pendant with a remaining gemstone

ancient hanger with 1 remaining gemstone, ? AD.,
pendant (13 mm / 1,21 g), (gilt) bronze, some remaining golden areas, encrustations, hanger detached,
Obv.: 10 circular holes small around bigger center hole with dotted border, 1 remaining gemstone (transparent, glass?) in a small hole.
Rev.: (blank).
.