How common is it to see luster only around the rim?

dan1ecu

I've got a mint state Columbian commemorative that is lustrous around the rims, but dull in the center. It's this way on both the obverse and reverse. Is this a sign of tab toning?

Thanks,
Dan

MrHalfDime

Seeing mint luster only around the rims is not uncommon at all. Luster results from the very fine metal flow lines as metal is moved under the extreme pressure of the coining press during striking. Luster is simply the reflection of light from the microscopic alignment of metal in the very top layer, near the coin's surface. Even dipping can remove these top layers of metal molecules, removing luster. The raised rim, combined with the proximity of raised stars and letters near the rims, protects the fields near the rim, resulting in obeservable luster in these areas even when the luster has been removed from unprotected areas due to circulation wear.

roadrunner

that usually means the coin is not uncirculated. Yet you will find many MS61-MS65 18th and 19th century type coins with that feature. Local B&M shops often sell raw coins like that as UNC.

By the time you get to 1860-1890, not having a full cartwheel on your unc coin is a no-no.

roadrunner