Help me solve a mystery
I love a good coin mystery, and this one has me seriously puzzled.
Here's a 1930-B British Trade Dollar, with chopmarks. In general the coin looks ok.
But there are 2 red flags with this coin.
The coin has little bumps of silver on the surface. (see pics below)
The chopmarks are about 30 years later than I'd typically expect to see, for this size and style, on a British Trade Dollar.
When I noticed the little silver bumps, I immediately thought cast counterfeit, so I studied the edge. The edge shows zero evidence of any sort of seam, even under microscope. I'm convinced it was struck in collar.
The coin weighs 26.84 g and the size is also correct. Before I purchased the coin, the seller verified the coin with a sigma verifier and it passed with no concerns.
So it seems the like the coin is real, but I can't get over the silver bumps on the surface. I also can't explain the chopmarks, outside of some remote locales were still chopmarking later than we currently understand. Large chopmarks of this style are known into the early 1920's at the very latest, but it's very rare to see them. Point being - it's possible these chops are authentic, but unlikely. Having said that, as someone who has studied many thousands of chopmarks, they look convincingly real to me.
What I'd really like to hear is if someone could explain the silver lumps on the coin. Thanks for any help you can offer.