Whoa.. whatever that could be is very interesting! I know what it is not.. not a CUD. CUD's are formed at the edge/rim of the coin. Your issue is on the field not near the edge.
Yes indeed, very interesting. Something also going on at the neck which looks too heavy to be die polishing. Can we also see the reverse?
"Freestanding Interior Die Break"?http://www.error-ref.com/interior-die-break-connected-to-die-crack/
Will you look at the strike on that, too? Get that one checked out. That's no ordinary error or ordinary strike for that matter. Let us see the other side of that.
You may not be able to find a photo of another half like yours. If it was me i would not want to be able to find a photo for raritys sakes. Error .com says this happens in all denominations. Here is some photos of other coins and specs on qualifications. http://www.error-ref.com/freestanding-interior-internal-die-breaks/
@Marine1, give this more time. We have experts who only check in here from time to time. I PM'ed one just now to drop in...
It appears to be an occluded gas bubble. The soft borders would be consistent with that diagnosis. It's definitely not a die break and the soft borders are not what one ordinarily see with die dents. If the surface of the elevation flexes when pressed down upon with a toothpick, that would confirm the diagnosis. If the roof of the bubble is thick, it might not flex, so failure to flex would not falsify the diagnosis.
Thanks for all the input and I have one more question, IF this is solid and not a gas bubble what would be the next step. I have a buddy who has access to a Metal acoustic tester and can determine if there is a internal pocket of gas (air) or if its solid. I have another 1964 Kennedy with a round raised dimple of about 1.5 MM in width that I posted some months ago and incidently was from the same bank bag as this one and was tested to be solid metal and not hollow. What is the best way to proceed and how to determine actual rarity. As usual any help would be greatly appreciated. M1
You should keep looking into it, if you're so inclined. For instance, were this a gas bubble, it happened at the planchet stage, and that's pretty coincidental how it's lined up against the back of his head. I mean, that's almost a perfect alignment. Likewise, were it off the die, one would expect there ought to be others, as one would expect it to repeat for the life of the die. Personally, I think it was on the die. Look at the field in front of his forehead. This error is in the field in back of his head. That whole lateral area was wasted. That's what those funny field lines mean. I'm just observing, that's another thing that stands out on this one, this error occurred in an area of the die that was stressed.
I fully understand the implication of this oddity and I thank you for your information. The coin will be checked with Non-distructive testing next week as well as the other kennedy with a similar dimple on his cheek, This is a bit above my paygrade however my curiosity is telling me to go for it. Ill post the results next week and again Thank you! M1 U.S.M.C. Retired
