Even though the Seated Liberty 20-cent series has two things going for it that other series don't, it's still indicative of the market for Seated Liberty era coins.

The 20-cent series is a short series. It encompasses just four years in total, 1875 through 1878. It is also an unusual denomination, making at least one a must-have for type collectors.

The 20-cent coin is technically not of exactly the same design as the other denominations of Seated Liberty coins because Liberty varies slightly and the eagle on the reverse is of another design than those used on the larger Seated Liberty denominations.

The designers are also different – William Barber designed the 20-cent coin and Christian Gobrecht designed the earlier Seated Liberty coins.

Seven coins comprise the 20-cent series, but one of them, the 1876-CC, is untouchable for most collectors. Only about a dozen to 20 pieces are known to exist, mostly in Mint State, and prices for this issue run well into six figures. So, most collectors forego collecting this date and Mint mark.

Some collectors also ignore the 1877 and 1878 issues, which are low-mintage Proof strikes only. They cost several thousand dollars, on up. Circulated examples are known, but are scarcely encountered in the marketplace.

In our recent update of the 20-cent series, most values increased by perhaps 10 to 20 percent. This includes the circulated examples of the more common dates, which sell for just a few hundred dollars, or even less, as well as the Mint State and Proof examples.

These increases are in step with those for the market for virtually all the Seated Liberty denominations. Blemish-free circulated examples are increasing in value and demand has picked up during the past couple of years, especially since the Jules Reiver auction of his comprehensive collection of Seated Liberty and other varieties.

If a dealer asks a price that seems too high for a given Seated Liberty issue, especially for a scarce variety, don't reject the price out of hand.

After all, the dealer has to make a business profit and his or her acquisition cost is also probably higher than what they were selling for just months earlier.

Such coins are also very scarce and it could be years until you have an opportunity buy another one.