The 1997 New Zealand $2 coin was recalled and melted down, the reason is unclear but it was minted without a rim which all the other years have.
It was recalled because the coin was slightly larger than other years (presumably because of the rim being absent). They were being spent in vending machines and would get jammed.
@offa the saxon As to the question asked in the thread title - there are many world coins that qualify as being a rarity. I've owned several with a total mintage of less than 150 coins, and others with a total mintage of less than 50 coins. But not a one of them was ever worth more than a few dollars, or melt value. My point is, rarity sometimes doesn't mean much when it's not accompanied by popularity. In other words, if nobody wants the coin, then rarity is meaningless.
Not necessarily but together they do drive price. You can have a huge supply of something but without demand, You still have a huge supply.
I saw a coin advertised on EBay a few years ago as unique. From what I could research at the time with my limited resources, it probably was. But because it was from a small African country and not the US, it sold for only $500 instead of $5,000,000.
And of course my counter to the point on value is that some collect for more enjoyment than just the narrow view of profit. A rare coin is hard to find, and that is the fun of it for me. So rarity gets much respect, the value another question, and one that was not asked for in the original query.
No, it wasn't. But since so very, very many equate rarity with value, it is worth pointing out that the two, rarity and value, often have nothing to do with each other.
I always did as well. I have bought many coins for my collection that cost but a few dollars - because I liked them and for no other reason. And by the same token I bought many coins for my collection that cost thousands of dollars - because I liked them and for no other reason. But because cost has such a huge impact on us in all other aspects of our lives, cost/value must be understood and taken into account when buying any coin.
From Numista: 1997 circulation issues were recalled in January 1998 because a slight variation in the metal composition resulted in many parking, gaming and vending machines rejecting them. This affected the coins' electrical conductivity, which is used as an authenticity test by many of these machines. It is unknown how many 1997 $2 coins remain in circulation.