Know if a Griswold cast iron skillet is real by looking for the tell-tale signs of a duplicate: poor casting, faint markings, orange rust and a feel that is heavier than it should be. Shrinkage occurs often when a foundry reproduces a real skillet, and the new skillet is often heavier.
It can be easy to recognize a duplicate skillet if you have an original to use for comparison, but this is often not the case. The only option for a collector is to acquaint himself with the heft and style differences between authentic skillets and reproductions. There are a lot of people out to make money by selling fraudulent duplicates.
Griswold's Erie No. 5 skillet is an example of how much can be lost if you don't know the methods to spot a fake. This skillet was only produced in 1907, and originals are worth as much as $650 to $700 in good condition. An antique collector can believe he is getting a great deal by buying one for $100, but the value of a duplicate is $5 or less. The Griswold & Cast Iron Cookware Association holds annual conventions that have examples and information on reproductions so members can avoid falling for scams.