Perceptions Of Rarity

rustyboy- Oh, supply and demand certainly is a determining factor concerning how easy a coin can be found on the market, but I am more curious as to how you perceive rarity in terms of mintage.

Mintages of silver dollars are largely irrelevant as millions were melted at several point in history. No one really knows for sure the number that actually survive.

It's slightly hypocritical to list the factors that make a coin rare and then ask about what mintage makes something rare. You obviously know that mintage does not determine rarity on its own.

What a red herring.

That is such a hard question to answer. There are just to many factors to consider other that just mintage.
Maybe if your talking 1804 silver dollar or a 1913 nickel where the mintage of the coin, is the reason these coins have a super value.
I would have to say, I do look at the mintage when I am looking to purchase a coin, but I also look at condition and popularity of that coin or series.
There are a lot of cases where low mintage coins are easier to acquire than a coin in the same series that has higher mintage. Like the 1950 D nickel. Another example is the 1932 D Wash quarter 436,800 vs 1932 S with 408,000, the 32 D has a little higher mintage but in MS60, Red Book value has it twice as much as the 32 S.
Where I am really puzzled by low mintage coins, is with modern commemorative dollar coins. There are many that have mintage less that 150,000 and some that get below 50,000. IMO the prices really do not reflect the rarity of these coins. And at some point, when more collectors decide they want to acquire complete sets of commemorative coins, some of these will double or triple in price.
So how would I answer your question, each coin has to be looked at on it's own merit, to determine how rare it is, and not just on mint released numbers.

Mintage numbers are deceptive as to actual rarity. Some coins have very high mintage numbers but are truly rare and hard to locate. Some have mintage numbers that have no bearing on the number of coins still outstanding due to melting or other loss. However, a coin with a very low mintage, especially a US coin, that has a strong collector demand will always be considered rare. (1877 IHC, 1909s IHC, 1909SVDB Lincoln, 1916d Mercury dime etc.) When you move over to the darkside it gets a little more interesting. Records can be hard to interpret, demand is hard to gauge, and sometimes the fates throw you a curve ball. Large hoards turn up and throw the supply/demand status out of balance. That can happen with US coins also, the 1903o dollar being a great example. With the coins I collect, Spansih Colonial Pillar Dollars (first coin listed in RedBook) the year 1754 shows Mexico mint output at over 11,600,000 pesos, but no breakdown by denomination. Assuming 50% of the production in 8 reales (experts believe closer to 85% based on other years when it is broken down, but go with me here) there would be 5,300,000 1754 8reales. With 4 varieties, 1,300,000 of each variety. Yet a study in USMexna Journal on 1754MoMM with crowns alike could only locate 25 or so known specimens in all the auction and sale catalogues researched. I have looked for 30 years, believe me that coin is rare despite the potential large mintage figure for the year. It is all supply and demand. US coins command a premium price compared to equal mintage foreign coins due to the affluence of America and the size of the collector market here.

As already said, this is not an easy topic. Rare coins are what you make them. For example of coins not rare and low mintages, look at the 1931S Lincoln Cent, 866,000. Or how about the 31D Mercury dime with the 4th lowest mintage in the series, 1,260,000 and not really worth much. 1912S Liberty Head Nickel also low mintage yet no real fantastic value.
The popularity of a coin, similar to a painting, is more of what makes it worth anything big therefore sort of rare.
Also, mintages are missleading. You could have a trillion coins minted but if almost all have been destroyed, except a few, that to makes it rare. Example is the 1974 Aluminum Cent. Not sure how many minted but most were supposed to be destroyed.

Maybe a better definition of "rare" would be how many exist on the open market, as opposed to how many are known (or assumed) to exist?