Rich M. writes: I have a new 1999 penny. It is significantly thicker than all the other 1999 pennies I’ve seen. Could it be a mint mistake? It is nearly double in thickness. Is it worth anything besides 1 cent? Thank You.
What you are seeing is extra height in the rim, not an increase in the actual weight of the flan. You can check this by weighing the coin. It should weigh 2.5 grams. This can happen if the striking pressure of that particular mint press was too high. That would force additional metal to the edge of the coin and increase the size of the already upset rim.
The coin could also have stuck to the die and actually struck other blanks (brockage). If this happens for enough blows of the press the resulting error can look like a cup. (At a visit to the Denver Mint with the ANA, I was shown a Eisenhower dollar with rims that were 2 inches tall). The reverse of the coin is usually deformed.
Note that U.S. coin blanks are cut from sheets of stock that are manufactured to specific standards. It is not likely that there would be stock that was twice as thick as normal. This would be detected immediately (The blanks wouldn’t fit through the feeder). Also, even if could fit, there would be tens of thousands or more of identical pieces in circulation. All would get stuck in standard counting machines. This would be a news item.
There is a collector base for coin errors and if the error is significant enough, the coin will bring a premium.
