The Rarest Of The Rare What Is It

That was an amazing collection. There are a lot of medieval rarities that are surprisingly affordable (but let's not let modern collectors in on it!).

I picked up a misattributed Liege briquet with two known examples for €240 from that auction, as well as a Liege double briquet variety that's unique -- I was able to trace the coin back to the 1800s via primary references (but not auction catalogues... yet).

Kunker offered a second-known 1492 Leeuwarden briquet variety later that year, but I had to let it go... I spent too much at that Elsen auction!

There are many affordable opportunities for exceedingly rare or unique coins off of the well-beaten track of slabbed moderns. That was one of the reasons I left US coinage for medieval/world coinage -- I want to own (and touch!) the ultra-rarities, not lament that I don't have millions to spend on a single coin needed to complete my Barber dime set.

Yes it is. I own two pieces that are unique. I had a third unique piece but eventually a second one was discovered. I tried to buy it, but the auction house didn't execute my bid and it sold for less than my max bid.

What the heck? I cry foul on that!

You would not have needed fractional ownership a few years ago.

I had not seen that this coin had been spoken about here. It has some time in a portuguese collection classified as a fake. Sold for 3400 euros when the collection was broken down. Described as a nineteenth century replica.
The collector was extremely reputable and would be difficult for him t have mis-attributed the coin. One of his focus was on the dutch portugaleser struck for use in Brazil of which he owned several. If he classified this one as fake he must have had motive.
I still think more likely this it is a nineteenth century imitation. The coin does not match the only die in storage that I ever saw a photo of. Or the drawing of the only known coin published in the nineteenth century, part of the van Doorninck collection. That one matched the die in storage. This one does not.
The minting was very low. And the finish is medal like, not coin like. Too perfect for coin to be used in commerce as was intended.
Heritage passed it as genuine but there were legitimate doubts about this coin. Was it a coin or a medal? Is it original from the time or a nineteenth century re-strike or replica with different dies?
It would be very helpful if the auction house had published a photo of a die in the Deventer museum that really matched the coin. Because this thing keeps being resold they can still put doubts to rest by publishing it. Can they?

Buyer beware. Only because it is sold by a famous auction house or boxed in plastic does not mean a coin called unique is unique. Or genuine. With unique coins there is much work to do to prove them genuine.

Thank you for sharing.

Has anyone mentioned the Ike dollar prototypes? Not unique, but ultra-rare and desired for an American coin.

https://www.pcgs.com/coinfacts/coin...v-007/519088

https://www.ikegroup.info/?page_id=1078

The rarest one I can think of is the 1945 steel Wheat penny

Its so rare that it doesn't exist!