You can identify or “attribute” your coin with knowledge of the following characteristics of it. These six points will help you to pinpoint the ruler it was issued under, the type of coin, the denomination and possibly the time and place of its minting.
Mint Mark and/or other markings
Weight: Usually given in grams with an accuracy of at least 1/10th of a gram, but it is better to have figures to 1/100th of a gram, this weight data will help with your determination of the denomination of the coin in question.
Diameter: Usually given in millimeters with an accuracy of at least 1mm, but it is better to have figures to 1/10th of a mm, this dimensional data will help with your determination of the denomination of the coin in question.
Die alignment: Die alignment is expressed in degrees and describes how the obverse and reverse dies were aligned to each other when the coin was struck. The best way to look at it is to put a straight edge on the face of the coin with the edge at the top (0 degrees) and the bottom (180 degrees) through the center. While holding the straight edge to the coin turn it over and note where the “top” of the reverse device is. If it is in the same place as the top of the front device it is called 0-degree alignment. If the top of the reverse is at the bottom it is called 180-degree alignment. Another way to examine die alignment is to hold the coin on the edge with the obverse facing you, your index finger at the top of the obverse design (0 degrees) and the thumb at the bottom of the design (180 degrees); then rotate the coin horizontally maintaining your index finger and thumb fixed on the same spot on the rim. The 0-degree alignment is called Metal Rotation, while the 180-degree alignment is called Coin Rotation. Now for the “real world”; Roman coinage was made using dies that were movable, so true 0 or 180 degree rotations were not always made. You must guess at the rotation, to the nearest 15 degrees, if it is not at the 0 or 180 degree mark. If you turn the coin over with the straight edge on it and the top of the obverse at the top of the rotated coin you must observe where the “top” of the reverse device is. If you observe that the top of the reverse device is pointing towards where the 3 would be on a clock face this is said to be 90-degree rotation. Or if it is pointing to the spot where the 9 would be on the face it is said to be 270-degree rotation.
Color: Color could help to determine the material the coin is made from, this material data will help with your determination of the denomination of the coin in question. Also by knowing the material you will know in what section of a reference book to look for your attribution references. The most likely materials are Gold (AU), Silver (AR) or Bronze and/or Copper (AE). There are several alloys of Bronze ranging from a high content of silver (alloy called Billon) to very little different metals except copper. Most are intermediate types with various metals alloyed with the copper to make the bronze, all are called AE in the nomenclature.
Obverse Legend (the wording on the front of the coin)
Spelling COUNTS!!!!!!!!!!!!!!! Note length of the legend, note breaks in the legend, the whole legend is a big key in the attribution.
Name of the issuer - This name is the single BIGGEST KEY to the whole attribution process. Without this name the whole process is much more complicated if not made almost impossible in some cases.
Titles or descriptors - These words or abbreviations attached to the issuer’s name will help to finalize the attribution. There are a lot of abbreviations that could be attached within the legend, such as IMP, AVG, COS, P, F, DN, GAL, VAL, A, M etc. Just one title could change the whole coin’s attribution.
Known legends - There are several places to find lists of legends like:
· Moneta or other software
· RIC, Sear, Van Meter or other books
· Web sites like the FORVM, WildWinds, Dirty Old Coins, etc.
These known legends are most of the time able to be attached to the various mints. One legend may be only used at a single mint. This is important information when you are looking for the various available places where a certain coin was made.
Partial legends – There are several places to find search engines of legend’s characters if you can only see a few of the letters. These are found in places like:
· Moneta or other software
Note: some letters are very common and will produce a long listing of possibilities. Examples of those letters are AVG, IMP, DN CAE, and NOB. While other combination of letters like POTXXXVII are very unique and return a short list if not a single hit when they are used.