I wish that Sear books had a rarity scale rather than value estimates. The Imperatorial book has a concordance guide showing Sydenham rarity scales, which I found useful.
I don't think it's possible to create a useful rarity scale for Provincial coins in a book like Sear's GIC.
The academic definition of "
Rarity" as it applies to
ancient coins, is based on X occurrences of a coin
type in Y number of comprehensive
collections of the series. As a hypothetical example, if in 30 comprehensive
collections of
Roman Republican coins, (e.g. British Museum,
ANS,
Hannover and 27 other
collections), a given coin
type occurs only 3 times, then it is judged as extremely
rare.
The problem with assessing
rarity of
Provincial coins is that for this methodology to
work, there has to be a large number of comprehensive
collections to
work from. This is why the "
rarity"
scales fall flat on their
face when
applied to either
Provincial or Late
Roman Bronzes, where museums have traditionally not bothered to try and assemble comprehensive
collections. If there is not enough data, then one cannot meaningfully make a
rarity table.
What one can do, is to make an assessment based on occurrence at
auction sales etc, as to how common a coin is. One can say whether a coin is common or not common (ie
scarce), but unless you have a huge database (I'm talking 10 times bigger than
Coinarchives, or very large numbers of comprehensive
collections such as exist for popular series) you cannot really say whether a coin is "
rare".
Roman Provincial Coins (the book series) addresses the issue by counting the number of cited specimens, but this is only valid as a
rarity indicator when the number counted is very low (5 or less). Above 5, then the issue is probably relatively common and the editors probably just included the first 10 examples available to them but perhaps if you
search well there are 100 examples easily available.
I myself made a
rarity scale for
Roman Republican bronze coins: which is here:
http://andrewmccabe.ancients.info/RomanRepublicBronzeRarities.htmlI counted 12,643
Roman Republican bronzes in making this table.
Still, it is really only valid as far down as "very
rare". For coins of greater
rarity, one cannot really tell from the few occurrences just how
rare they
rare. One cannot distinguish between "very
rare" or "excessively
rare" as there are few examples of both.
Bottom line, for
provincials, not only is it not useful to make a
rarity scale in a book such as
Sear GIC, but it is probably not easy to make a
rarity scale in any book, yet.