This is more of an overview of different alteration methods found from several sources, including a reference guide. Alteration is different from making counterfeits because where some counterfeits are struck, alteration uses already existing geniune coins, and 'alters' one digit of the date (or more) or removes the mint mark, or may also add the mint mark. There are several methods counterfeiters use. 1) Tooling 2) Application 3) Embossing Tooling is a rather outdated practice because counterfeiters have begun to use more specialized methods. It involves using scrapers, gravers, blades and such to alter or rearrange details of a coin. One such example is a 1944-D lincoln cent altered to have the date become a 1914 D. This can be detected through different spacing between the date numberals and tooling marks. Application is the opposite from tooling, instead of altering a coins date (Changing the 4 to a 1) something is added. A mint mark is taken off a coin (usually shaved) then glued or soldered in place. When it is gone, this leaves glue residue behind which can be detected. Soldering is much more effective, but one has to be more careful. With gluing, the mint mark is positioned on the coin's field and held with a toothpick. The problem with this is the glue will act to cover oxidation of the coin, it will not tone the same as the rest of the coin because of the glue applied. It can be removed (and easily detected) by no damage to the coin by applying a drop of acetone on a swab to the mint mark. With soldering, usually a coin is plated (which is more necessary for silver) to cover up all of the solder marks. Faint tooling can sometimes be seen through a loupe. Embossing is the process of using a small partial die (having only a mint mark on a small area of flat field) and pushing the coin's metal up into th e die space to add detail. The only down fall to this is a hole has to be created somewhere on the coin for the mint mark to get inside. The hole will have to be filled in and there will always be traces of tooling marks used to create the hole. Detecting altered US coins (some examples) The 1909-S VDB Lincoln Cent With this coin, somtimes they are struck and sometimes details are added. Brian Silliman says sometimes he sees the letters "VDB" added to the reverse. A few struck counterfeits are known, but a very exceptional counterfeit will be explained below. This coin differs from in a few articles where the author explained how a counterfeiter used a pair of very well made 1909-S VDB lincoln cent dies to overstrike a genuine 1960 cent. The dies struck the genuine coin with enough pressure to obliterate almost all of the host coins details and bring up the impression of the S-VDB cent! So in other words a 1960 geniune cent was used a host coin, and a 1909-S VDB die was used to overlap the details onto the 1960 cent and bring up the details from the dies of the S-VDB Cent! A few faint diagonostics are visible: a flattened liberty just above the sharply overstruck legend, (from the host coin) and traces of the date on the host coin. (The original numberals "19" below the overstruck coin) The key is to understand luster, be familiar with the series in questions details. Another example of a altered coin is an 1889 Carson City Morgan. With this coin, a process was used as explained earlier using a reverse of a P 1889 morgan where the denticals meet the rim and replaced it with a CC Mint reverse from a different and more common year. Because part of another coin was inserted, it emits a distinct "thud" when dropped, not a ring that silver has. If you look at where the denticals meet the coin, where on a geniune coin it would be smooth and crisp, on counterfeited/alteration coins the metal was moved to conceal the space between the rim and denticals of the inserted CC reverse. Discoloration from oxidation of a glued mint mark can be a sign that the mint mark was added...it's important to look for evidence of a steam along the base of the mint mark. Discoloration from solder may be the result of the heat used to apply it, or chemical changes in the epoxy used to glue to stick the mintmark on. Some general guidelines for identifying key date alteratoins, the key is to understand the geniune characteristics of the mintmark in question for that period, Is it consistent with that period? Knowing what a geniune coin's characteristics are for a paticular date and knowing your series is key to detecting counterfeit and altered coins. 1909-S VDB Lincoln Cent Geniune characteristics. 1. The "S" mintmark must have serifs which are vertical and parallel to each other 2. A small die chip is found inside the upper loop of the "S" mintmark on the obverse. 3. Sometimes high grade coins will show a depression in the upper serif of the "S" mintmark on the obverse 4. The center crossbar of the "B" in the V.D.B on the reverse must be diagonal, not horizontal. Also check for tooling, scratches, displaced metal polising or cleaning to conceal evidence of the mint mark on this coin. Embossed mint mark, as explained earlier, is where someone drills a hole into the coin to place the mint mark. On 1901 S 25c's, look for seams around the mintmark. On 1893 S mint alterations are most common, 1894 S $1have a die gouge on leg of eagle. Picture of an altered mint mark, notice the discoloration around it. Sources: Numismatic Forgery Brian Silliman Notes from class Brian Silliman Papers on alterations PCGS Guide to grading and counterfeit detection Altered 1856 indian cent (flying eagle) Altered 1944, notice the spacing between the numbers. (thanks to ziggy29 for the post)
