From the photos, your coin looks like an antique greek-macedonean gold coin (probably a stater). Besides this,one coin's sides looks like severely damaged in circulation or by man's hand. But...all these are from photos.
To know something for sure,we need:
1) accurate weight of the coin.
2) that you ask,at a jeweler's shop,if your coin is made of real gold or not! Your coin may be genuine or a copy/fake. If you'll find out it's real gold made,then your coin is 100% authentic. If the coin is just gold plated(?),then it is 100% a copy of almost no value.
In order to tell you possible collectable value,please come back to us with the jeweler's answer + a macro photo of the coin's side opposite to that with a head (Alexander Macedon,probably) + the coin's weight.
Hi FL --
Here's what a genuine one looks like. Your coin is faithful to the inscriptions and pattern, but is smashed in several ways, probably post-mint damage and gold harvesting by a crook. Your coin looks genuine, but smashed, to me. Andi's gold test is super-important. Use a non-destructive test (e.g., an XRF machine).
Here's the auction description for the one in my picture. Yours is probably worth 1/4 of this one due to its smash-ness!
Roma Numismatics Ltd > Auction XX Auction date: 29 October 2020
Lot number: 305
Price realized: 11,000 GBP (Approx. 14,195 USD / 12,174 EUR / 13,013 CHF)
Seleukid Empire, Antiochos I Soter AV Stater. Aï Khanoum, circa 266-261 BC. Diademed head of Antiochos I to right, with elderly features / Apollo Delphios, nude, seated to left on omphalos, testing arrow in his right hand, left hand holding tip of bow set on ground to right; BAΣIΛEΩΣ to right, ANTIOXOY to left, ∆ to inner left. SC 435.3; ESM 703; HGC 9, 122. 8.49g, 18mm, 6h.
Mint State; lustrous fields. Extremely Rare.
From a private English collection.
Estimate: 15000 GBP