Sadly, fakes of these coins have been pouring out of China for some years now. By all accounts, many do indeed look good and "sound good" - the Chinese fakemasters have apparently become expert at making cheap alloys that look and sound just like solid silver. Most don't weigh good, but yours is close - very close. At less than a gram underweight, it's much more convincing than usual.
We see them occasionally here on the forum;
this one posted last year is the same design as yours. Jtr's example, Scoutjim's example and the one on
zeno.ru are all shoddier and more "fake-looking" than yours, but I'm still highly skeptical that this one could be genuine.
The weight given on the coin, the bottom line of script on the bottom pic, says "7 mace 2 (candareens)" - it's a dollar, or claiming to be one, anyway; the character for "candareen" is actually missing. That alone leads me to be suspicious.
I suspect someone's taken their dies for the fantasy tael and modified them to resemble a pattern dollar (Pn8 or Pn15), which according to Krause were never actually struck in silver (they weren't even struck in China; they were Birmingham Mint patterns). But they forgot that the script for the dollar weight was six characters long rather than 5, and rather than squeeze the missing character over on the left hand side and making the legend assymetrical, they simply left "candareen" off, and hoped no-one would notice.
I can't be absolutely certain of this theory, however; genuine patterns are so scarce, I can't find a picture of one on the net or in my books to confirm it, so
maybe the genuine ones have "candareen" missing as well. But I doubt it. I certainly can't find any other Chinese dollar with this critical character missing.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis