Authenticators in the past relied heavily on a coin’s physical properties such as weight, diameter, thickness, color, and specific gravity to determine its authenticity. Today, our task has become more difficult. This is because counterfeits in general have become more sophisticated and deceptive. Many modern die-struck fakes are made within the tolerances of genuine Mint products, so measurements are of less help than they were in the past. At the same time, more “problem” coins are being sent to grading service providers.

Among the greatest challenges to coin authenticators are eighteenth and nineteenth century gold or silver type coins with no original surface remaining. The measurement of coins in this condition is seldom useful, due to the metal loss associated with them. Additionally, whizzed coins and coins that have been harshly cleaned, repaired, or recovered from the ground present special problems because, in many instances, they can look similar to counterfeits.  Read Full Story