When reviewing the coin in hand remember a few key facts:
1. Weight is 27.0 grams - wear will not really account for too much loss. Most people over-estimate the weight lost. Be suspicious of any coin in VF or better that weighs less than 26.6 grams. The majority will be forgeries at that weight or less. The correct weight should be 26.8 grams for VF.
2. The edge design is critical especially for Mexico City examples. There are full weight silver forgeries that date to the 1890s, so be careful. A real 8R has TWO areas of overlap on the edge. These 2 overlaps are exactly opposite one another and they are the same length.
3. The circles and Rectangles on Mo9 mint issues are well formed - irregular shapes - square cornered circles - variations in spacing are all signs of likely forgery.
4. The edger apparatus in Mexico City was equipped with dies that had retainer lips that PREVENTED rapid side to side wobble. The edge design should run straight and evenly around the edge.
5. Counterfeits have irregular edges - the full weight silver forgeries often have ONE edge overlap. They sometimes have distinctive grip marks - diagonal slashes that are visible on top of the design on HALF of the edge. /////// I believe these are traces of the mechanism the forgers used to edge their planchets.
6. The forged dies are often made with softer steel and are prone to surface degradation (lumps and bumps in the fields). Be suspicious if there are too many raised lumps.
7. Off metal copies especially those made in Birmingham, England from 1796 to about 1800 used well engraved dies and the coins were Sheffield Plate. These are detectable by Specific Gravity testing only (unless you want to cut the coin
).
8. Modern Chinese copies are usually rather obvious in person. They have awful fields with numerous raised scratches from tooling the die surfaces. These forgeries use various transfer techniques to make most dies but all suffer from a loss of fine detail and a lack of sharpness at the transitions.
9. There are then the obvious types where the design elements are wrong - a comparison of details will give you what you need to do this check.
Once a forgery is detected - the next step is to determine if it is junk or not. The Sheffield Plate Birmingham counterfeits for example are far rarer than originals and they bring high prices. The 1890's silver forgeries are treated as ORIGINALS by most dealers since they can't distinguish the type.
Old crude off metal forgeries made with hand engraved dies are often very collectible. Modern nickel or steel copies with REEDED edges are absolutely WORTHLESS.
Posted 02/14/2010 2:36 pm
