Different authors and different publications use different criteria and ways to determine and represent the rarity of particular coin types. It has to be noted that the rarity in most publications is based on information which is twenty, or more years old and does not reflect the data from Internet offerings. Since our attribution is based mainly on the ten volumes of Roman Imperial Coinage (RIC), and because the rarity has different criteria in the different volumes we are offering a rarity reference table here. The number of coins reflects the number of specimens in major collections.

RIC Volume I (London, Spink and Son Ltd., 1984, 1999 reprint, p. xxii)
R5 - Unique
R4 - Rare - up to 5 specimens known
R3 - Rare - about 10 specimens known
R2 - Rare - about 15
R - Rare - about 20 known specimens
S - Scarce
C - Common

RIC Volume II (London, Spink and Son Ltd., 1926, 1997 reprint, p. vii)
R - Rare
R2 - R5 - increasing degrees of rarity (not specified numbers)
S - Scarce
C - Common
CC - Very common

RIC Volume III (London, Spink and Son Ltd., 1930, 1997 reprint, p. ix)
R - Rare
R2 - R5 - increasing degrees of rarity (not specified numbers)
S - Scarce
C - Common
CC - Very common

RIC Volume IVi (London, Spink and Son Ltd., 1936, 1998 reprint, p. ix)
R - Rare
R2 - R5 - increasing degrees of rarity (not specified numbers)
S - Scarce
C - Common

RIC Volume IVii (London, Spink and Son Ltd., 1938, 1998 reprint, p. ix)
R - Rare
R2 - R5 - increasing degrees of rarity (not specified numbers)
S - Scarce
C - Common

RIC Volume IViii (London, Spink and Son Ltd., 1949, 1998 reprint, p. viii)
R - Rare
R2 - R5 - increasing degrees of rarity (not specified numbers)
S - Scarce
C - C3 - increasing degrees of commonness (not specified numbers)

RIC Volume V part I & II (London, Spink and Son Ltd., 1927 and 1933, 1998 reprint, p. x)
R - Rare
R2 - R5 - increasing degrees of rarity (not specified numbers)
S - Scarce
C - Common

RIC Volume VI (London, Spink and Son Ltd., 1967, 1997 reprint, p. xvii)
R5 - Unique
R4 - Rare - up to 5 specimens recorded
R3 - Rare - up to 10 specimens recorded
R2 - Rare - up to 25 specimens recorded
R - Rare - up to 50 specimens recorded
S - Scarce - in most major collections
C - Common - in every major collection
C2 - Very common - Common in every major collection

RIC Volume VII (London, Spink and Son Ltd., 1966, 1997 reprint, p. xix)
R5 - Unique
R4 - Rare - 2-3 coins known
R3 - Rare - 4-6 coins known
R2 - Rare - 7-10 coins known
R - Rare - 11-15 coins known
S - Scarce - 16-21 coins known
C - Common - 22-30 coins known
C2 - Common - 31-40 coins known
C3 - Common - 41 and more coins known

RIC Volume IX (London, Spink and Son Ltd., 1933, 1997 reprint, p. viii)
R - R5 - increasing degrees of rarity (not specified numbers)
S - Scarce
C - C3 - increasing degrees of commonness (not specified numbers)

Feel free to email us with any questions you may have.