This 34mm coin was found buried underground during the construction of my grandmother's home around 40 years ago. The construction took place in a city called Multan (southern Punjab, Pakistan). I have been keeping it for 14 years now but never got to know how old it is. Now I've moved to Germany and I'm doing my Ph.D. in Physics but only recently I got curious again about this coin or pendant.
I find it strange that a Chinese Zodiac coin/pendant was found buried in Multan which is 3000 kilometers away from the nearest big Chinese city (Chengdu). Maybe someone dropped it on their journey on the ancient silk route or perhaps it was carried along an ancient river in Multan that has now dried up.
P.S. I am not asking for the worth of the coin as I am not willing to sell this coin (it was a gift from my late grandmother). I just want to know how old it is. Like the story behind the coin i.e, it's age and origin. Any help will be greatly appreciated. Thanks in advance.
Coin Diameter: 34mm
Coin Thickness: 2mm
Note: The coin is not perfectly circular as it seems to have a clasp that has been smoothened with time. Hence, the reason I think it might have been a pendant. As for the hole that was drilled into it later.

