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Author Topic: How rare is rare  (Read 1042 times)

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Offline emcee

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How rare is rare
« on: January 09, 2022, 09:28:36 pm »
Posting on descriptions of coins offered for sale in the Forum's frequently describe coins as " scarce", "rare" or "very rare." I would like to know what the known population is to be described in those categories.  I have at least one coin that another site describes as "rare, under 20 known" but I am skeptical about the accuracy of the claim.

Offline Dominic T

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Re: How rare is rare
« Reply #1 on: January 09, 2022, 09:40:59 pm »

Offline emcee

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Re: How rare is rare
« Reply #2 on: January 09, 2022, 09:52:31 pm »
I think I may be more confused than when I started but I'm fairly confident that every Roman coin I own would be considered rare by someone putting a Lincoln Cent collection together.

Offline SC

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Re: How rare is rare
« Reply #3 on: January 10, 2022, 06:55:12 pm »
No one knows all the coins that have been found or where they all are, no one.

So statements like "one of twenty known" mean various things and you need to read the fine print to see what they mean in any given case.

The easiest is published/public collections.  So there are 20 known in the ANS, British Museum, Bibliotheque Nationale, Berlin, Vienna, etc.

Or someone is also following major auction houses - including through some online services that track such info.  Thus the 20 includes museums and auctions.

Or someone has checked all online websites.  And did they just search today or have they been looking and keeping records since 2000?  Or someone who has tracked all eBay sales, etc.  Again, for how long.

The accuracy of such a statement largely depends on the coin type too.  For a gold aureus it is fairly safe to assume that most, but certainly not all, sales and examples could be known.  If someone did the full research and found 20 known I would personally assume there were under 30 in existence. 

But for a late Roman bronze with a specific mint and field mark the listings are only the tip of the iceberg.  Even if someone kept long term detailed records I would assume only a small fraction of what was out there was included.  Huge numbers of such coins sell in unrecorded bulk or direct in person trade, etc.

SC

SC
(Shawn Caza, Ottawa)

Offline Johan W

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Re: How rare is rare
« Reply #4 on: February 15, 2022, 05:28:20 am »
 +++ +++ +++

Offline Anaximander

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Re: How rare is rare
« Reply #5 on: February 15, 2022, 07:53:03 am »
Shawn has the right idea. As a practical matter, I look to the cited references and the date of that reference.  Some are more credible than others.

Sydenham (CRR) offers a number from 1 to 10, but failed to define the terms (!).

If a Greek coin is listed in Oliver Hoover's Handbook of Greek Coins series as Very Rare ("R2"), that's using Arthur Houghton's rating system. His definitions are nicely specific, yet carry a lot of caveats.  Have a look at his expanded definition, prepared with David Hendin and appearing The Celator “Defining Rarity,” June 2008 (Vol. 22, no. 6) and posted in his website. You'll see that this definition was written specifically for Seleukid coins.  And the ratings were thought, then, to be good only for about 10 years.

In Houghton and Hendin, rarity is a function of frequency (in something of a statistical sense) of a coin's appearance in publications and collections -public or private- or is estimated to exist in public or private hands.  Yes, that is necessarily imprecise and open to challenge, but it is an opinion, at least.  To amplify Shawn's point, these opinions should be backed by data and kept up-to-date with the trove of information now available on coin finds and the publication of collections and sales in the last 20 years. 

Offline Joe Sermarini

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Re: How rare is rare
« Reply #6 on: February 15, 2022, 07:24:03 pm »
When a reference includes a rarity table, that table will be included on the NumisWiki page for that reference.  RIC I, HGC 2, Emmett and Varbanov I, for example, have rarity tables on their NumisWiki pages. This information is important especially because for some references R1 means very common (the R only indicating it is a rarity scale number not rare), while for others it means rare.

If you click on rare, this is what you will see on the NumisWiki Rarity and Scarcity pages...

Scarcity and Rarity

Also see ERIC - Rarity Tables.

Rarity ratings for ancient coins in sales catalogs, including FORVM ANCIENT COINS' shop are based on some or all of the following:

- Published rarity ratings when available (such as those in Roman Imperial Coins below).
- The number of examples in published collections and other references.
- The number of examples in certain hoards.
- The number of examples sold in auctions over the past years.
- The number of examples currently on the market.
- The number of examples on the Internet.
- The number of examples handled by the cataloger or dealer in the past.
- The knowledge and experience of the cataloger.

An exact degree of scarcity and rarity of ancient coins is rarely certain. Also, the rarity of a type can change if a new hoard is discovered. Often coins that were once listed as rare in references are only cataloged as scarce and coins that were once scarce are cataloged as common today. Although unusual, a cataloger may also believe a coin is rarer than a published rarity rating or the number of examples in collections implies. Highly desirable coins are found in disproportionately high numbers in publications and collections because they were sought for each publication or collection with greater effort than other coins. Such coins may actually be quite scarce or rare. Also, the cataloger may know or think a published rarity rating is in error.

Another rarity consideration is how narrowly the type or variant is defined. A rarity rating might apply to the general type or to a narrowly defined variety. A particular coin of a short reigning emperor may be listed as common but overall the coins of that emperor are much rarer than those of Constantine, for example, who issued millions of coins. Yet, many Constantine variants are identified as rare or even extremely rare. Rarity might even refer to a specific mint workshop (officina) or control mark on the coin. The same issue applies to Greek coins. The coins of a city in general might be common or rare, but even in a city that issued many coins, the coins of a specific magistrate, with a certain monogram or a specific control mark might be unpublished and thus rare. Rarity is sometimes based on an obscure magistrate name, officina number or control mark because some collectors are interested in obtaining all of the variants of the type.

The impact of price on the rarity of coins is entirely dependent on demand. A rare variant may not cost much more than a common variant of the same type with similar eye appeal. On the other hand, a rare variant or type might be much more expensive if there are a number of collectors that find the type desirable. The greatest impact of rarity on price applies when the specific rarity is necessary to complete a highly collected series. Consider that some U.S. coins are extremely expensive when only the date or mintmark varies from millions of others of the same type. Collectors need to "fill a hole" and the price reflects the demand created by that need. Fortunately, for most ancient coins the need to "fill holes" does not apply to the same extreme - even some extremely rare, unpublished, and even unique coins are sometimes still affordable.

RIC Rarity Ratings

See Emperors and their RIC volumes if you are uncertain which volume below applies.

RIC I (1984)
Sutherland, C.H.V. The Roman Imperial Coinage, Vol. I, From 39 BC to AD 69. (London, 1984).
C: Common to very common
S: Scarce
R: Rare
R2: [Rare] 11-15 known [in the collections examined]
R3: [Rare] 6 to 10 known [in the collections examined]
R4: [Rare] 2 to 5 known [in the collections examined]
R5: [Rare] Unique [only one in the collections examined]

RIC II (1926)
Mattingly H. & E. Sydenham. The Roman Imperial Coinage, Vol. II: Vespasian to Hadrian. (London, 1926).
Unspecified, probably the same as RIC I

RIC II, Part I (2007)
Carradice, I.A. & T.V. Buttrey. The Roman Imperial Coinage, Vol. II, Part 1: From AD 69 to 96. (London, 2007).
C2: Extremely common
C: Common
R: Rare
R2: Very rare
R3: Unique [only one in the collections examined]

RIC III (1930)
Mattingly, H. & E. Sydenham. The Roman Imperial Coinage, Vol III, Antoninus Pius to Commodus. (London, 1930).
Unspecified, probably the same as RIC I

RIC IV (1986)
Mattingly, H.B., E.A. Sydenham & C.H.V. Sutherland. The Roman Imperial Coinage, Vol IV, From Pertinax to Uranius Antoninus. (London, 1986).
Unspecified, probably the same as RIC I

RIC V (1927 & 1933)
Mattingly, H., E.A. Sydenham & P. Webb. The Roman Imperial Coinage, Vol V, Part I, Valerian to Florian. (London, 1927).
Mattingly, H., E.A. Sydenham & P. Webb. The Roman Imperial Coinage, Vol V, Part II, Probus to Amandus. (London, 1933).
CC: Very common
CC: Very common
C: Common
S: Scarce
R: Rare
R2-R4: [Rare] Additional degrees of rarity
R5: Unique [only one in the collections examined]

RIC VI (1967)
Sutherland, R.A.C. & C.H.V. Carson. The Roman Imperial Coinage, Vol VI, From Diocletian's reform to the death of Maximinus. (London, 1967).
C2: [Very] Common in every major collection
C: [Common] In every major collection
S: [Scarce] In most major collections
R: [Rare] 26-50 coins known [in the collections examined]
R2: [Rare] 11-25 coins known [in the collections examined]
R3: [Rare] 6-10 coins known [in the collections examined]
R4: [Very Rare] 2-5 coins known [in the collections examined]
R5: Unique [only one in the collections examined]

RIC VII (1966)
Bruun, P.M. The Roman Imperial Coinage, Vol VII, Constantine and Licinius A.D. 313 - 337. (London, 1966).
C3: [Common] more than 41 coins known [to the writers when the book was written]
C2: [Common] 31-40 coins known [to the writers when the book was written]
C1: [Common] 22-30 coins known [to the writers when the book was written]
S: [Scarce] 16-21 coins known [to the writers when the book was written]
R1: [Rare] 11-15 coins known [to the writers when the book was written]
R2: [Rare] 7-10 coins known [to the writers when the book was written]
R3: [Rare] 4-6 coins known [to the writers when the book was written]
R4: [Very Rare] 2-3 coins known [to the writers when the book was written]
R5: Unique [only one in the collections examined]

RIC VIII (1981)
Carson, R., H. Sutherland and J. Kent. The Roman Imperial Coinage, Vol VIII, The Family of Constantine I, A.D. 337 - 364. (London, 1981).
Unspecified, probably similar to RIC VI or VII

RIC IX (1933)
Pearce, J.W.E. The Roman Imperial Coinage, Volume IX, Valentinian I - Theodosius I. (London 1933).
C-C3: [Common with] increasing degrees of commonness
S: Scarce
R-R4: [Rare with] increasing degrees of rarity
R5: Unique [only one in the collections examined]

RIC X (1994)
Kent, J. P. C. The Roman Imperial Coinage, Volume X, The Divided Empire and the Fall of the Western Parts, AD 395 - 491. (London, 1994).
Unspecified, probably similar to RIC VI or VII

Notes:
- Although RIC rarity is often criticized, better ratings are not available elsewhere.
- RIC rarity is wrong for many individual coin types but overall they are fairly accurate.
- Some of the RIC volumes are quite old and the ratings are dated. These volumes have many types listed as rare that are scarce at best, yet overall they are still fairly accurate. Most R5 coins are not unique but are very rare. Most R4 coins are also quite rare.
- Older volumes were based on older collections that tended to have more Western mint coins and fewer Eastern mint coins. Since many coins are now found with metal detectors in Eastern Europe and the Middle East, the rarity of Eastern mint coins is more likely to be overstated.
- Rarity of very interesting types and coins of very rare emperors are probably understated because extra effort was likely expended to acquire those types for the collections examined.
- For RIC volumes that list the rarity of types by each officina the accuracy of rarity for the whole type is usually more significant and the least rare officina considered. Specialty collectors may, however, disagree and an R5 coin for a particular officina is probably very rare even if the type is not.
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Offline Joe Sermarini

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Re: How rare is rare
« Reply #7 on: February 15, 2022, 07:31:36 pm »
One thing that has come up several times here over the years... We have had people post that an R5 (unique) coin is now an R4 because they have found the now second know specimen. If you find a coin that is R5, it does not change to an R4. The rarity ratings in publications are static and do not change until a new edition is published (if ever). R5 (unique) does not mean the coin actually is unique or that anyone should expect there is only one existing specimen. It only means that the author only knew of one specimen.
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Offline emcee

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Re: How rare is rare
« Reply #8 on: February 17, 2022, 01:55:50 pm »
This appears to be a topic for which there is no answer that can be nailed down tight.  Morgan Dollar collectors may fixate on if the eagle has seven tail feathers or eight but with my ancient coins, I don't care. I have seen listings on eBay where a coin is described as "Rare coin to identify" which I find rather unconvincing. There is an ERIK listing of rarity by emperor but not individual examples.  I'm curious what the numbers are like for that.

Offline Joe Sermarini

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Re: How rare is rare
« Reply #9 on: February 17, 2022, 02:15:15 pm »
...There is an ERIK listing of rarity by emperor but not individual examples.  I'm curious what the numbers are like for that.

Nobody can answer that except for a few usurpers where there are very few know.
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Offline cicerokid

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Re: How rare is rare
« Reply #10 on: February 17, 2022, 04:03:47 pm »
 Athens NewStyle, 2 Palms, Only 4 known , I have one in my collection, the other 3 are in museums, Athens NewStyle Demeter & Artemis 3 known 1 in BM, 1 in St Petersburg and  mine from the Selton collection.

Now that is rare and published by me

John
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Offline Jay GT4

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Re: How rare is rare
« Reply #11 on: February 17, 2022, 04:52:43 pm »
One thing that has come up several times here over the years... We have had people post that an R5 (unique) coin is now an R4 because they have found the now second know specimen. If you find a coin that is R5, it does not change to an R4. The rarity ratings in publications are static and do not change until a new edition is published (if ever). R5 (unique) does not mean the coin actually is unique or that anyone should expect there is only one existing specimen. It only means that the author only knew of one specimen.

Yes, that's true, except on a few occasions when I've submitted a coin for inclusion in an upcoming addenda.  When I get confirmation it is accepted I then I make a note that it has been submitted and an R3 coin can now be considered R2.  Or better yet, when a new type is submitted I mark it as R3.

This is the fun of being a specialist collector.

Offline Serendipity

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Re: How rare is rare
« Reply #12 on: February 18, 2022, 06:51:26 am »
I greatly respect the professionalism and scholarship of the Forum and generally go along with its scarcity and rarity ratings when cataloguing my ancient coins. None of my modest number of Roman and Greek coins are either scarce or rare. A recent Byzantine gold coin I acquired is described as scarce. Some other Byzantine gold coins that I intend to add to my collection in the future are described as very rare or scarce.

 

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