Everybody who has ever collected coins by date and mint mark has experienced some form of what I call completion anxiety, the irresistable urge to buy that one last coin that will complete your set of Lincoln Cents or Barber Half Dollars or Honduran 2/UN/10 Centavos or whatever, and free you to go on to bigger and better things.

The feeling usually sets in when you have acquired about 90% of the pieces generally accepted as making up a "complete" set, and begin counting the remaining holes in your album with disturbing ease. Although individual tastes may vary, "complete" is commonly held to be one piece struck at each mint in each year that the series was struck.

Therefore, if you are collecting Morgan dollars by date and mint, you would need four coins for the year 1880, or one each from Philadelphia, Carson City, New Orleans and San Francisco. By the way, the order that your album arranges the mint marks in is irrelevant; Wayte Raymond used to list them in his revolutionary National Coin Albums in the order that the different branch Mints were established, i.e., C, D and O (all tied as to year, so alphabetically), S, CC and D, while R. S. Yeoman originally copied this format in his vastly successful Whitman albums but later changed to alphabetical order for the sake of copyright novelty. Either is correct.

Varieties such as overdates fall into a grey area, as they are usually considered to be an important part of an early series such as Capped Bust Halves, where overdates can be both common and spectacular, but are virtually ignored (today) among Morgan Dollars. Part of this has to do with how well a given series is researched and how popular it is among collectors. Large Cents are collected by miniscule varieties (at least among the later dates) because of the loving detail given to the early dates by M. Vernon Sheldon in "Early American Cents" and "Penny Whimsy," and even though there are occasional new discoveries the 1793-1814 series numbered by Sheldon as S-1 through S-295 is considered to be closed and potentially collectable.

This brings you to the concept of Non-Collectible coins, which Sheldon designated such as NC-1 or NC-2, etc., where so few pieces of a variety were known that the average collector could not reasonably hope to find one, and so Sheldon numbered them outside of his normal numbering sequence to keep the hope of completing the numbered set alive. A good example of this is the 1793 "Strawberry Leaf" Cent, Sheldon NC-2 and NC-3, of which only four specimens of the two varieties combined are reported. Although every Large Cent collector would love to have one of these, few will ever achieve completion.

Other series have such stoppers, such as the very rare 1888/7 Indian Head cent, though the demand for varieties varies tremendously based on whether or not the series is commonly collected in albums and whether or not there is a space for the variety in the album. The 1922 "No D" Denver Cent and the 1955 Doubled Die Cent are worth many times what they would have otherwise been had holes for them not been included in the Whitman Bookshelf albums, though they are always available for a price, while the 1888/7 Indian Cent is almost impossible to find but is not included in the albums.

The 1913 Liberty Head Five Cents piece (or nickel) much in the news recently is another bonafide stopper, although some would argue that it is not a true coin but rather a Mint sport or piece de caprice. Be that as it may, it is a famous coin with only five pieces made, two of them in museums and two in private collections with the fifth unaccounted for.

Two 1966 Jefferson Five Cents were reportedly struck in Proof for presentation to the coin's designer, Felix Schlag, in honor of his initials FS being added to the design in that year, but the present whereabouts of the duo is unknown. These are not generally considered as a stopper because of the existence of millions of virtually identical Special Mint Set coins, and it is even possible that the coins have already been accidentally resold as such.

The Seated Liberty Half Dime series contains a powerful show or series stopper, the unique 1870-S piece only discovered in 1981. Although only one person can hold a "complete" set of Seated Half Dimes at any given time, I remember working with James G. Johnson, the first person to correctly research and explain the 1894-S Dime, at Coin World back around 1975, and helping convince him to buy an 1864 Half Dime I had discovered among a local collection. Jim only collected circulated coins actually issued for circulation, eschewing Proofs and special issue coins, and once I proved to him that the 1864 was a regular issue date (it had been incorrectly listed as a Proof-only issue for decades) he was happy to get the piece, though it still left him one hole, the 1802, from achieving completion as he saw it.

Another unique Seated coin is the 1873-CC No Arrows Dime, believed to be the sole survivor of the 12,400 pieces struck before the standard weights for the Dime, the Quarter and the Half were changed early in 1873 and the old-weight coins were ordered remelted. Curiously, it is not listed in either the Encyclopedia of U.S. Liberty Seated Dimes by Kamal Ahwash or The Complete Guide to Liberty Seated Dimes by Brian Greer.

This rarity is believed to owe its existence to the sorely-missed U.S. Assay Commission, which annually examined representative samples of each batch of precious metal coins produced at each Mint to verify the quality of the metal used. It has long been speculated that surplus, untested coins may have found their way into the Mint Collection, which at the time was displayed at the Philadelphia Mint where the Assay Commission met, or else strayed into the hands of Philadelphia dealers friendly with high mint officials. The 1873-CC No Arrows Dime and the four known 1873-CC No Arrows Quarters may have reached safe harbor via the same route, and we should be glad that they were not all destroyed.

The aforementioned 1894-S Barber Dime, with perhaps ten Prooflike Uncs. and two well-circulated specimens known, is another big stopper that most collectors will never own. Whitman Coin Products, I assume out of consideration for the collectors who would forever face this nagging hole in their simple blue folders, recognized the likelihood of completion anxiety by not punching out the hole in the folders but rather by leaving a cardboard plug in its place. Jim Johnson did complete the first circulated set of Barber Dimes ever known, but I do not recall how he housed it. He may have used one of the fancier Bookshelf albums, which did have a hole for the 1894-S Dime to inspire the advanced collector on.

The last stopper Dime is surprisingly unheralded, the 1975 "No S" San Francisco Mint Proof error of which only two specimens are known. I had the privilege of seeing the discovery set when it was sent in to Coin World for examination, and have been searching for another one ever since. However, none of the Roosevelt Dime albums include holes for the various "No S" errors in the series, and so few people, if any, experience completion anxiety over this coin.

A more famous stopper is the 1876-CC Twenty Cents piece, with perhaps 16 to 18 pieces known, which makes completion of the otherwise temptingly short "double dime" series so difficult. Ten thousand of these were struck, but most were melted in March of 1877 when the series was abandoned for looking too much like a Quarter (a la the Susan B. Anthony Dollar). Most of the survivors are more or less Uncirculated, so some or all of these may have survived via the Assay Commission route.

The 1817/4 Capped Bust Half Dollar, with only eight or nine pieces known, is the heartbreaker of that series for the members of the Bust Half Nut Club. The 1853-O No Arrows and Rays Seated Liberty Half Dollar, with three specimens known despite there being no record of its mintage, is just a dream for most members of the Liberty Seated Collectors Club. By the way, the correct order of the words Seated Liberty and Liberty Seated, like the order of mint marks, is subject to personal preference, though one is a bit more grammatical.

At least a great collector like Louis Eliasberg had the hope and the opportunity to acquire most of the great rarities mentioned to date, but even he was never able to acquire an 1873-S No Arrows Half Dollar or an 1873-S Seated Dollar. Both are recorded as having been struck, but not one specimen of either is known today despite the exhaustive research of Harry X Boosel, who once owned the finest set of 1873 coinage ever assembled.

I personally believe that the 1873-S Seated Doller was never actually struck, but was rather a phantom bookkeeping entry created to account for the delayed release of leftover 1872-S dollars that couldn't quite fill up a bag in 1872, but on this point Harry and I amicably disagree. The 1873-S Seated Dollar remains a psychological hole in the minds of many a Seated collector, and was even mentioned in the Ellery Queen mystery novel "And On The Eighth Day."

The 1804 Silver Dollar has long been called the king of American coins, with but 15 specimens known divided among three different varieties. To many collectors the acquisition of an 1804 Dollar would be the dream of a lifetime, and demand remains such that no less than four of the specimens changed hands in 1993. Most collectors, however, will never be able to afford the half million dollars or so required to buy one, making it more of an impossible dream to us numismatic Quixotes.

The 1884 and 1885 Trade Dollars are even scarcer, with but ten of the former and five of the latter struck, but for some strange reason most date collectors reject them as mere fantasy coins created at the Mint for one of the Mint's dealer friends. The 1964-D Peace Dollar is currently unknown in any collection, though it is reliably reported as having been released in limited quantities and may eventually outlive the Mint officials responsible for its quite innocent production who would rather see it dead.

In the gold series there are many famous rarities such as the 1849-C Open Wreath Gold Dollar (5 known), the 1854-S Quarter Eagle (9 known) and the unique 1870-S $3. The rarest of many rare early Half Eagles are the 1822 date, with but three pieces known and two of these in the Smithsonian Institution, and the 1854-S date with but one of the three known in the SI. Though few people would ever attempt to collect these early series by date today, many people attempt to complete the relatively short Indian Head Half Eagle series only to find the 1929 date surprisingly elusive. We have been looking for one for a client for a year, and have seen only one piece come and go at auction in this time. Though not as rare as the 1822 by any means, the 1929 is certainly a formidable roadblock.

The rarest post-1804 $10 coin is probably the 1875, with but 100 business strikes and 20 Proofs made, but the biggest series stopper is certainly the 1933 of which perhaps 30 to 40 pieces survived the Gold Surrender Act of that year. The Indian Head $10 is a doable series, but is not for the faint of heart or wallet.

The unique 1849 pattern $20 currently in the Smithsonian is not really considered to be a part of the series, but is certainly desired by all serious collectors. The 1861-P Paquet reverse is widely recognized as a great rarity, with but three specimens known, but questions linger as to whether they are regular issues or trial strikes. On the other hand, the 1886 $20 with 1,000 business strikes and 106 Proofs made is a powerful stopper to many a year set of Liberty Head Double Eagles, a popular alternative to full date and mint collecting, since no branch mint coins were made that year.

Finally, the St. Gaudens $20 is our most beautiful series and one of the most challenging to collect, disregarding the rare pattern varieties, since all but a handful of pieces from no less than nine different years and Mints never left the Mints and were remelted in 1933. These include the 1920-S, the 1921, the very rare 1927-D, the 1927-S and everything struck after 1928. The 1933 is considered illegal to own, though a few have surfaced outside of the United States only to go back into hiding.

With the advent of slabbing for rare coins, are albums for series of coins still relevant, and if they are not will people lose the urge to complete sets so as to "fill up all the holes?" Can most series before 1907 even be attempted these days, or did date and mint collecting die with Lilly and Eliasberg?

The crystal ball grows cloudy, like a slab that has been to a hundred coin shows too many. All I know for sure is that I cannot keep high-grade 1909-SVDB Cents in stock, and have sold three 1911-D $2-1/2 Indians in the last three months to date collectors. Also, the correct number of pieces for a complete set of Honduran 2/UN/10 Centavos is two, and I only have one to go. I hope.

(Author's note: Several years after whimsically writing this reference to a scarce Honduran type coin, I discovered an unknown date, 1910/08, for the 2/UN/10 Centavo coin, thereby raising the number in a complete set for the type to three. I still need the 1907.)

Originally published in COINage magazine in February, 1994 under the title "Coin Stoppers." Reprinted with permission. Copyright 2002 by Thomas K. DeLorey.