Coins, banknotes and pieces of exonumia in the Numista catalogue are assigned a unique number, denoted as “N#”. This number uniquely identifies a type of coin, banknote or exonumia. It is visible on the pages of the Numista catalogue.
The N# number can be used each time you want to refer to about a specific item. Here are some examples where it may be useful to identify a coin, banknote or exonumia type:
For example the number N# 1196 represents the French 10 Franc Montesquieu coin.
The N# contains only digits. Unlike some other reference numbers, it is not sequential and it doesn't convey any logical information; also, the N# numbers don't repeat for different countries or periods. The only purpose of the N# number is to have a permanent, immutable, and unique identifier.
If you know the N# number of an item, you can quickly find it in the Numista catalogue using the search bar at the top of the website.
In some contexts, Numista also lists the NN# number. The NN# number refers to a specific version of a coin, banknote or piece of exonumia. If a coin is minted with the same design and characteristics for several years, with different mintmarks and with different variants, the different year, mintmark and variant combinations share the same N# number but they each have their own NN# number.
For example, the US Columbian Exposition Half Dollar has the number N# 4396. The 1892 coin is identified with the number NN# 23112 and the 1893 coin is identified with NN# 23113.