7.9 Clamshell Errors
When a lamination error is sufficiently large and occurs deep enough within a planchet, the lamination can appear to split the coin in two along the edge. Such an error is commonly referred
to as a clamshell error.
While most commonly seen on coins composed of copper-nickel alloys, clamshell errors are generally rare on silver coins. The following images show an example of a clamshell error where the
lamination opened up near the edge and spread through the middle of the coin. On this coin, the clamshell is an unusual shape due someone attempting to pry open the clamshell.
Clamshell error
