@new, I'm going to move your thread over to the ancient's subforum so that we can get some good eyes on it. In the meanwhile, can you please add a pic of the edge plus the diameter and weight of this piece? Thx.
"If you climb a good tree, you get a push." -----Ghanaian proverb
"The danger we all now face is distinguishing between what is authentic and what is performed." -----King Adz
Nice. Drachm, struck in the name of Alexander the Great. (Well worn, and lots of glare, but I think I can make out the AΛ of AΛEΞANΔΡOY to the right of Zeus on the reverse.) Probably a posthumous issue, perhaps late fourth century BC. It's an iconic ancient type, with head of Herakles wearing a lion skin headdress for the obverse, and a reverse with Zeus seated left, holding an eagle and scepter. Varieties were struck at a number of different mints over a long period.
Once you have it in hand, a better photo of the reverse, without the glare, might allow us to pin it down to a mint and narrower date range. Especially important will be a better image of the monogram below Zeus' throne.
From my research on-line I think it is an Antigonos I Alexander the Great AR Tetradrachm 315-311 BC. The problem is the angle of the bend in the arm on the reverse never matched a picture exactly. It is about 3cm and weight is 16.71 grams.