The error attribution is appropriate as long as the proper tests have been done to determine that the dark streak is something besides 90% silver(copper-rich perhaps?). There is another possibility- a foreign piece of metal was rolled into the planchet stock when the thickness was being set. However, I have to assume that a PCGS grader/attributor could determine whether that was the case or not by examining the coin in-hand as there is a distinct difference between an alloy issue and an extra metal issue.



















