The Rarest Of The Rare What Is It

One interesting one is the 1933 Saint-Gaudens double eagle, of which there are several in existence but only 1 that is legal to own...

Logically, a coin with zero known surviving examples is even rarer than a coin with just one surviving example.

The 1964-D Peace dollar. 316,076 were struck, every single one of them was melted down again before they could be released. Not even the Smithsonian or the Mint kept a copy; the two they put aside in the Treasury vault were ordered destroyed in 1970. If any mint worker managed to smuggle one out, they've done a good job of hiding it for the past 60 years.

For a combination of rarity and value, outside of the United States, the "rarest coin" is probably the gold 1000 mohur coin, struck by Mughal emperor Jahangir (father of the guy who built the Taj Mahal) in 1613. The coin is 8 cm thick, 20 cm across, and weighs just under 12 kilograms of .917 fine gold. Original mintage: just one. It was lost and presumed destroyed for several hundred years, before turning up again back in 1987. It was last seen in 2008 in a Swiss auction house, with a $10,000,000 estimate attached to it. Mughal mint records show that two other 1000 mohur coins were struck in different years; these were given as gifts to foreign dignitaries and presumably melted down into something more practical shortly after the dignitaries arrived back home, as they have never been seen again.

The British Museum doesn't have any 1000 mohur coins in its collection; all they have is a brass copy of the much smaller 100 mohur.

The 1000 mohur coin would remain "the world's largest gold coin" until the Perth Mint and the Royal Canadian Mint got into a "who can make the biggest gold coin" war back in the early 2000s. The Perth Mint won that contest, with their 1-tonne gold kangaroo "coin" made in 2012, but that giant coin was later broken down again as nobody could afford to buy it. Second-place were the Canadians with their 100-kilogram maple leaf dated 2007, which had a mintage of 6; one was stolen by thieves and destroyed in 2017, leaving five survivors.

The 1964 Peace dollar would be my guess. While the official explanation is that all were melted no one actually counted them. I've spoken to people that heard rumors that several exist but since they are technically illegal to own one you would be really dumb to say you have one as the government would take it away. So in effect it is the rarest coin due to:
1) officially all are melted
2) if you actually owned one you couldn't talk about it
3) if the us govt knew you owned one, it would be considered stolen property and they would take it away.
4) you can't get it certified to prove 100% authenticity (so if you have one how can you prove it's real)
5) there are enough rumors around that there maybe a few out there but cant be proven (see above)

So while a few 1 coin samples are known of other years/denominations the 1964 Peace dollar is like Schroedingers cat of coins in that it exists and doesn't at the same time.

I wonder what floats around the coin black market. Coins that are illegal to own, but are desirable and bought by those who want them.

For Australia, any 1937 dated coin other than the Crown. 1930 Pattern pennies

New Zealand - Waitangi Crowns, but there were 3 failed patterns of them which are basically unique, one sold recently for $30k.

Rumours also abound about a 1959 strapless 6d, a 1985 50 cent coin with a Canadian dollar planchet reverse and 1940 Halfcrown with the standard Obverse.

That is very interesting. If that were to happen, meaning it exists, then would the legality of the Carr over-strikes becomes a hot topic?

NumisEd asked...

Because it was never issued for circulation and should have been destroyed once it was recalled by the Mint.

This is much like the 1933 $20 gold Double Eagle coins that were minted but never issued or the 1964-D Peace dollars that have been deemed Illegal to own and are subject to seizure by the Secret Service if they are found.

Thirty-six 1974-D aluminum cents were distributed among the House Banking and Currency Committee and the Senate Banking, Housing, and Urban Affairs Committee. Nine congressmen and four senators received examples, along with some Treasury officials. Additional specimens were given out by then Mint Director Mary Brooks.

Ultimately, the proposal for the aluminum cent was rejected in Congress, due mainly to the efforts of the copper-mining and vending machine industries, which felt the aluminum coins would jam machines and cause other problems.

More than 1.5 million aluminum cents were destroyed with two known surviving. Both of the coins known have been graded, with one getting an ICGC AU-58 that was then submitted and regraded by PCGS as a MS-62. The second coin was graded PCGS MS-63 ( https://www.PCGS.com/cert/28544237 ) with a price guide value of $250,000. It has been discussed that the true value would be $2,000,000 or more.

If a coin is struck but never issued, all examples are considered the property of the US Mint and cannot be legally owned by an individual.

@Conder101. I missed your reply! I was just trying to help NumisEd with his question. My reply is just a rehash of what you had already said and wasn't meant as a disagreement in any way. Sorry about that!