I do not have any black coins, and do not foresee acquiring any. Cheers, RickO
Click on this link to see my ebay listings.
Looks like they were lubricating the dies with graphite or coal shavings at the mints.
I won this on the Bid Board of my local coin shop 30 years ago. I’ve never known what to make of it. It’s interesting how many of the coins posted here are classic silver commem’s. Was something going on in the prep of these coins?