I'd agree that it's a fantasy coin made specificaly for jewelry, designed to imitate an 1899-S gold double eagle. Not sure why they chose one of the more common dates to duplicate, but such a piece would be a cheap alternative to a genuine double eagle, even if the copy was made out of gold.
The seemingly random words on there "Prize Chinese Modern Elower" seems to indicate that the target market for this coin is non-English speakers who are not familiar enough with the language to tell the difference. This is commonly seen today on fake Chinese coins offloaded on tourists--the design is a good match and it might even be genuine silver, but it's just a cheap knockoff.
At least your piece is made out of real gold--most people who come on here with similar coins aren't lucky enough to have something that's actually valuable.