On the reverse of this 1898 coin I noticed a tiny "blob" beneath the letter U in the word Trust. It's definitely is a raised mark, not a gouge. I checked all of my other Morgans' and this was the only example. Any thoughts how it came to be? (Just a curious fan of these beautiful coins) .
From this vantage point it looks like some metal was moved to the left. There's a shadow on the right.
Under magnification the small lumps are metallic with no evidence of the metal being raised from a near hit. The surface is totally smooth. If the coin took a hit wouldn’t it be evident?
Could be. I would say a "hit" is different than a "stab". I have not examined the said coin in person and so have no actual first hand knowledge of the circumstances of the damage. From my experiences of having stabbed a multitude of various things, when you stab something, with say, a hunting knife, the point goes in and, as it goes downward and deeper, it creates a vertical entrance into the stabbed item. It also spreads, in this case the metal, apart as it goes deeper. That is what it looks like to me. It appears it was stabbed, with the knife having entered the coin and spread the metal apart. It does not look like a "hit". That is my opinion....that you solicited....and I provided. Nothing more. Take a large sharp knife and stab down wards into either a piece of silver or a block of wood. You will get a similar "wound". The "wound" will be smaller in the silver and larger in the wood, but, I believe, the wounds will both be similar to the "wound" in your coin.
Absolutely it did not. The OP is simply wondering what could have caused it. Certainly nothing at the mint caused it. I was only providing my best guess, which is a stab from a sharp and pointed knife. In truth, only the person who caused it, knows what implement and/or in what manner it was caused.