1981 Nickle Error- Monticello Not Stamped

Is the weight of your nickel the same as other nickels? Under weight would make your coin thinner than a normal nickel. If that is the case, it would explain the weakness of the strike. But closer images would also be a help. There could be a different issued that could also cause this as well. A Struck Through Grease issue. Also I notice there is damage on the obverse devices. Possible coin wrapper damage or vending machine damage. But looking forward to more images. Also include images of the edge with a normal nickel above and below you nickel. Kind of stack on top of each other to compare thickness. That would be a great help.

I believe this a Struck Through Grease error.

There are also signs of it in the word "monticello" and "five cents"

PMD here too, Montecello is the highest point on the coin, and the deepest part on the die, so It wouldn't make sense that grease would go that deep without affecting any other device. What does make sense is that Montecello is the highest part on the coin, it would be the first to be affected if it were a parking lot coin or someone rubbed it against something. You can see scratch marks in the area.

Here is some information on Struck Through Grease:
http://www.error-ref.com/?s=grease
Thinned planchets:
http://www.error-ref.com/?s=thin+planchet

The current images show your concern, but would like to be able to zoom into the details a bit more, before trying to make a final conclusion.

Elements currently presented have me thinking two directions at the moment that clearer images may resolve. Thanks, Doug.

There is a possibility that this was an abnormally hard planchet. Check the nickel image here:
http://www.error-ref.com/?s=planchet+void

Pete good info link.

I can take more pictures if needed. Yes Pete, that was a good link. It does look like this coin, Hard planchet ( not sure what that is) but it is only the top part of the Monticello structure.