Elizabeth II, New York Exhibition Crown Prooflike, 1960
In 1960 the Royal Mint issued only its second crown for our new Queen, Elizabeth II. But some were issued for the British Pavilion at the New York Exhibition. You can tell these because they are Prooflike rather than matt Uncirculated.
I believe that the 1960 crown in any condition is the most difficult Elizabeth II crown to find. The Prooflike one is much underrated and to be honest, most collectors are not even aware of it.