Hello Sarah --

Welcome!

Take your coin to a jeweler and get a precise weight, to the nearest 0.1 gram. Genuine Yunnan dollars weigh 26.8 grams. If yours weighs that, wham-o, it's genuine. If not, it's a fake.

After looking at 1000s of coins, you start to get a feel for authenticity by the overall quality of the strike and overall appearance of the surfaces. The strike on your coin looks mushy and the surfaces look un-natural. But I could easily be wrong. Internet photos are not suited for coin authentication. The weight will tell.

For pictures of a genuine coin and a fake coin, plus more info and approximate value, go to this page:

https://coinquest.com/cgi-bin/cq/coins.pl?large=17910