Alan , on some added mint marks you can see where they don't join the fields of the coin , there will be a little separation you can see . Especially with one of your scopes . So check to make sure the bottom of the mm is attached to the fields all around the D .
The PCGS book also states the mint marks are boxy and squared , and as the curve of the "D" begins to take shape on the right side, the top and bottom are angled and not rounded . Still I'd compare it to a known D mint mark used on a known good coin .
I'm not an expert here but that D looks pasted on. Shouldn't it be about worn off on a coin in that condition?
I absolutely agree. The bottom of that MM would and should have exhibited some wear and started to blend with the rim. I'd say it was added.
I also find it quite odd that the mint mark is so clear whilst the rest of the coin is quite worn down. Get someone who is well versed to examine the coin for you.
If you have a microscope our a X20 loupe , check out the mind mark for tooling within the D and around it. Furthermore,look for a seam where the D would be laying on the field. Sometimes it's quite hard to see a seam as it can be obscured by dirt or toning. Moreover, some coin doctors are quite good at doctoring/ adding MM, dates so they are even more difficult to spot. Good luck, and I hope it turns out to be a true 1916 D.
I agree with others. At first blush, the D looks like it should be worn for an AG like this. Most of the time a coin in this grade, if a mintmark is present, it becomes hard to distinguish if its a D or an S. I have pulled many 1916S coins out of 1916D slots in folders, put there by optimistically minded, (and eyed), young collectors.
The images of the whole coin were done on a scanner. The next 2 images were done with a Dino-Lite Here is a close up of the mint mark without diffusion and here is the same view with the light diffused
Those look a little better to me actually sir. There was a thread on CT a few years back on mintmark positions and shapes on the 1916D. I would search that thread and see what it says.
To me the D is not worn enough to match the rest of the coin and on the closeups of the D I see what looks like solder all around the D...looks like clumps and on the bottom pick the clumps even look like a different color.
You mean this thread?: https://www.cointalk.com/threads/data-1916-d-test-your-authentication-powers.101697/