Rarity Pt.2: Rarity Scales and Relevance

Common. Scarce. Rare. Very Rare. Unique.

 Collectors have attempted to determine the difficulty involved in obtaining the objects of their desire since collecting began. Pertaining to coins, numerous catalogers, authors, auctioneers, etc. have thrown the above descriptive words around (sometimes seemingly at random) to convey the relative scarcity of individual coins. Through the research of Dr. William H. Sheldon, the 8 point rarity scale he popularized for early date large cents around 1958 has become the most common quantitative rarity scale in use today and is commonly used for other coin issues as well. Here it is:

R8     Unique or nearly unique (1 to 3 known)
R7     Extremely Rare (4 to 12 known)
R6     Very Rare (13 to 30 known)
R5     Rare (31 to 75 known)
R4     Very Scarce (76 to 200 known)
R3     Scarce (201 to 500 known)
R2     Uncommon (501 to 1250 known)
R1     Common (More than 1250 known)

It’s important to understand that coins can move between rarity levels depending on new discoveries. Previously unknown examples come to auction frequently, and other events such as hoard discoveries have contributed to this in the past as well. Another important point is that these upper and lower limits are estimates. Any rarity scale will be imperfect. The idea is to take rarity out of the realm of mere guesswork. The true measure of the validity of the scale can only come through time, and Dr. Sheldon’s attempt has held up well when compared with other endeavors.

In 2009, Q. David Bowers proposed the Universal Rarity Scale in his book “The Whitman Encyclopedia of Colonial and Early American Coins”. The scale is expanded to include 16 divisions from URS-1 (unique) to URS-16 (16000 to 31999 known), each successive division doubling the one prior.

Back in the first part of this effort to define rarity I mentioned a question that came to me from Robert Wasserman. He wanted to know how rare in general Massachusetts Pine Tree coinage was thought to be. I would say that the vast majority of Pine Tree coins in existence today are of the shilling denomination and that the average variety falls somewhere between Bowers’ URS-10 and URS-11. So for the series, the varieties most people are apt to own have around 250 to 1000 examples in existence.

And now to put this topic to bed, here’s a quote from Jack Robinson’s new edition of “Copper Quotes by Robinson” : “No one really knows what rarities are. They were assigned a long time ago. They have been modified as populations became better defined and identified…Maybe they are in the ground, oxidizing away, or in undiscovered drawers…but by any stretch, they are speculative.”

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