
During the early the 19th century many foreign coins enjoyed wide circulation here in the States. Charts illustrating these foreign coins with line drawings and converted values in dollars and cents for gold and silver pieces were published in the various counterfeit detectors.
One of the most common types circulating were the Spanish Colonial silver "pieces of 8" and the fractions of 4, 2, 1 and 1/2 real. Being quite popular, the "pieces of 8" were subject to widespread counterfeiting.
Illustrated is such a deceptive counterfeit struck or cast in copper and with a good silver wash and with an actual weight of 27 grams, it probably passed quite freely in the "outback" or rural areas. That is until the silver wash wore off and the copper started showing through. Notice there are various test scratch marks in the obverse field.

With the detailed listings we have in modern coin catalogs, a numismatist will quickly notice the errors in the lettering, such as the reversed "D" in "DEI" in the obverse legend along with the rather odd spacing and uneven lettering. The real clincher though is the Mexico City assayer's initials of "F. M." for Francisco Arance Cobos (1777-1803) and Mario Rodriguez (1784-1801), while this coin is dated a bit too late in 1807.