besides weighing it which will really help narrow it down, the weakness of the "D" in dollar on the reverse does raise a red flag. I believe the best outcome here is a cleaned Trade Dollar.
try checking it to see if it will stick to a magnet . some of the older fake coins from China sticks to a magnet. I have a fake trade dollar and your's has the brown spots like mine has. I can clean mine and it will start to turn a tan color within weeks.
Rather than try to authenticate a coin in a series you are not completely familiar with, I'd pass on it. Especially considering the number of fakes versus real ones out there. If you have your heart set on a trade dollar, buy a slabbed one from a reputable dealer.
Lol have you seen Matt's threads recently on faked slabs? I am not buying, just trying to determine if a friends coin is real or not.
Then I'd say this is a perfect opportunity to learn the series a bit if he lets you take the coin for a day or two. If you can find a book or enough information, I think it would be interesting to hear your conclusion.
Real or fake it probably won't stick. If it's fake the magnet will slide quickly. If it's real the magnet will slide slowly when the coin is held at a 45* angle.
Very interesting. I have never heard of this method before. What is the theory behind this test? Just curious...
There are several videos on youtube about the subject and I am not a professional. Basically silver is diamagnetic and creates a weak magnetic field when subjected to a strong magnet. Here's one that shows the idea.
