found this partial coin and from a professional stand point is coin next to it a proof or circulated strike
The partial coin looks like PMD - Post Mint Damage And the other coin you would have to post a picture of the Obverse side also
The 1990 Proof Cent was minted in San Franciso with the S mintmark. Yours does not have the mintmark. Unless you have the rare no S mintmark variety. I want to share this website with you - http://proofsetguide.com/1990-proof-set/
It isn't necessarily the rim that needs to be flat. Even circulation struck coins have flat rims. It is the side edge that should be flat, with sharp 90º angles to the field.
no its same color the half have other half with date somewhere here in house lol will locate it soon n and read in pgcs that the 1990 has sharp edges as a proof and round edges as 1990 p so i believe the pgcs content on that
and about the 1990 no s i posted then it was terminated for some reason was verified as a mint coin and the half wasn't pmd as quoted earlier but i guess the most skeptical remarks are posted 1 IN A MILLION CHANCE WHO KNEW I'D BE THAT ONE
Could you add some of these (......) in those last two post? Hard to understand what you are trying to say.
Partial coins do exist, the thing that worries me is how strong the rim is, most fragments won't get that nice of a rim, most will be struck quite off center too, the wear is too even, like it circulated for a while and then got clipped, and error like that probably won't get that kind of kind of wear. It could be an error but my guess is PMD