Classifying coins or coin catalogs
Ever wonder why when you see coin catalogs they are listed in a particular order? Well it is not just the OCD parts of us coming out, it is for ease and consistency. When numismatists (someone who studies coins) started getting bigger and bigger collections they decided that a format that everyone would use would make looking at each other’s collections, as well as selling and buying coins, would be good. As it would happen coins have a great classification system, date, mint, design and denomination order.
If a particular coin was only made in one particular year with one, two of a few designs, that’s how they would be itemized in a reference book, auction catalog or dealer list. For example, all Lincoln Cents from the first year of issue in 1909 until 1958, had the same front and back. In 1959 the back changed and stayed exactly the same for the next 50 years. In 2009, additional reverse (back) varieties were introduced.
Years are chronological, years are easily understood and read by most collectors. Numbers (or Hindu–Arabic numeral system) move on one direction, and in set increment. We love numbers. So sorting by date is the first step. (Well some might say sorting by type/denomination is first, but I am assuming you would not put all your coins in numerical order but not sort first by demolition).
Next up you sort by mint. With Philadelphia being the primary mint for US Coins, goes first, then other mints by alphabetical order
Philadelphia (no mark or P)
Carson City, Nevada (CC)
Charlotte, North Carolina (C)
Dahlonega, Georgia (D)
New Orleans, Louisiana (O)
San Francisco (S)
West Point (W)
Now as a caveat, not every coin denomination was made in every location and Dahlonega and Denver never were operational at the same time, so the date would determine which mint it was produced at.
As we talked about above, some coins change over time, well to be honest all of the change in your pocket looks different than it did 50 years ago, heck even 10 years ago. Lately the US Mint is hyper excited about making new designs. The quarter is a perfect example, if you have anything in your pocket since 1999 then there are numerous designs. So for this level of classification the order is by the issue that they were released by the US mint.
And that is about it classifying coins is as simple as: date, mint, design and denomination order. OK it would state with country of origin, but I am guessing you knew that.