Thank you for the advice. Yes, I read the forum rules post albeit after posting :-/
i hadn’t considered a pendant, thank you. There is erosion and clear daylight through parts of it so its lack of uniform density could indicate a pendant...
Found while digging in the garden; it does ‘look old’...
It is one sided and around 2cm in diameter, wafer thin but quite heavy for its size...
Seemingly, there is illegible lettering? (2 words?) and a 6-pointed star on the lower right.? And does it resemble a Roman figure?...
It actually looks more like a late medieval/early Renaissance era knight to me:
The cyan is a helmet, with a chinstrap and a plume; the red is his sword, and the yellow is a shield with an unknown coat of arms; I see a six pointed star and a slanted banner.