I was also going to say the mint mark should not be so worn as the higher relief features around it. And again, goofiness beyond the norm for the level of wear.
Don't beat yourself up about this one. You didn't put it in that album, and if you got the coins for spot, there's no loss.
The wear from 6-7 o'clock from the rim to the mint mark isn't consistent with the rest of the coin. it's almost as if the edges were purposefully worn except around the mint mark so that you could tell it was a "D".
It , the MM looks fake to me as the inside should look like a triangle , though 4 reverse dies were used . Though 2 were repunched MM . JMO as I don't collect the series and this info is from the PCGS book .
Here is a previous thread that describes the various "good" mint marks. https://www.cointalk.com/threads/data-1916-d-test-your-authentication-powers.101697/ Is this information of help? BTW, I am not convinced that it is a cast fake. I have seen real coins that are severely worn with the same appearance. Better photos would be nice (like the photos in the link).
Well, I think I've seen that 1st photo before (the album page). Was that from the seller, and did you get these on eBay last week? If so, I'm really regretting not having upped my bid!!! Dang. But congrats, because I'm fairly certain you have the real deal. Congrats again!
I don't think it's cast. The mintmark position looks close to either die 2 or 3. Both of those are repunched but due to the wear you may not be able to see anything there. I don't think anyone here could give you a definite answer as to it's authenticity from the pic. If there's a dealer in your area you might try running it past him. Also for a start you could weigh it and/or test it to see if it's actually silver.
Hmm. I wouldn't have paid "genuine 1916-D" money for it, but I would've certainly snatched it up at the price you paid. Given the uncertainty expressed so far in this thread, I might even spring for grading/authentication -- but I'd wait a bit longer for more opinions.
The mint mark appears more defined in your first set of photographs and less so in the second set. However, all bets are still in play.
I think its a real merc I can't call whether someone altered the mintmark tho I'd say it stands a chance I'm no expert on mercury dimes tho
It's nothing personal. You know why Numismat said that, it's because there have been a few occasions where someone new joins the forum and pretends not to know anything about a rare, valuable coin that's clearly a counterfeit. And it's obvious that they're phishing for someone to PM them and say, "Hey, I'll give x dollars for that coin." It's a common scam tactic on coin forums.