FYI - I have received a communication from the Mint that Rockwell Hardness Testing (C Scale) is performed by them on production dies.
Fred Weinberg - thanks! Just to clarify...this is not my coin in the photo by the OP. Also very interested to learn the answer to Rockwell...
I think Fred is correct, however there are circumstances in which a mark can be identified as "likely". Elsewhere, I have noted the following...
Thank you!
Thank you @masterswimmer. I am thinking that the value in my taking the time to respond in such a way is not necessarily for the OP, but as an...
As I understand, you are saying this is a raised feature. That would indicate an indentation on the die which would certainly be from a Rockwell...
a Kennedy missing dual clad https://sullivannumismatics.com/coin/ngc-50c-1966-kennedy-half-dual-missing-clad-layers-au-55-0
Same coin $100 less https://sullivannumismatics.com/coin/pcgs-10c-1980-p-roosevelt-dime-dual-missing-clad-layer-copper-core-ms-62
https://www.ebay.com/p/1980-P-10C-Roosevelt-Dime/170430067?iid=254093817077&rt=nc
My reference is a post by Sullivan Numismatics Here is another...
Here is a reference by a reputable Error dealer https://forums.collectors.com/discussion/comment/11266774/#Comment_11266774
Here is a reference http://www.error-ref.com/missing-both-clad-layers/ What has not been seen, to my knowledge, is a full weight, fully struck...
Look for a scale which weighs to 2 decimals at least and takes AA or AAA batteries (easier to change)
It looks to me like your quarter has environmental discoloration. Were it missing clad, weight would be less than normal. Quarter weight missing...
I would be interested to know the thickness of the coin in mm to 2 decimals. The coin is just slightly heavy. Expected weight/tolerance:...
Agree - not missing clad layer. Were it missing clad, Missing one clad layer weight approximately 5.8 g - 6.1 g
Nickel Oxide is black and Copper oxide is black. The cladding is cupronickel
Perhaps check thickness with calipers at 4 points around circumference. Expected thickness = 1.52 mm -0.102/+0.152 mm
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