The coin looks somewhat like many Byzantine coins I have seen but there are some things about it that make me think it is either not genuine or it is not Byzantine. The color appears to be off for gold but that may be the white balance setting on your camera. The coin is cupped like many Byzantine coins. It has a full-face view of Jesus on the obverse like many Byzantine coins (at least I think that is Jesus on the obverse - he appears to have a halo around his head). But the lettering does not look like lettering I have seen on Byzantine coins. (The lettering on your coin would perhaps preclude it from being an Islamic coin of the type similar to the Byzantine coins.) I am far from an expert on Byzantine coins but I am looking at a cupped bronze Byzantine coin I have and the obverse and reverse designs are much smaller relative to the diameter of the coin than yours; the designs on your coin are only slightly smaller than the coin itself. If I were you I would start by translating the Latin words on the coin (it would really help if you could identify an emperor) and then looking for the coin among known Byzantine coins. Good luck and keep us posted on what you find out.
Looks to me like a charm made to resemble a Byzantine coin. But I'm no expert on Byzantine coins either.
