A "double die" on a penny (or any coin) refers to a coin that has been minted with a die that struck the coin multiple times, resulting in a noticeable doubling of the design features. This is a specific type of minting error primarily caused by the misalignment of the die during the engraving process.
Here are some key details about double die coins:
1. Cause of Double Die
- Die Creation Process: In coin minting, dies are created using a process where an image is engraved onto a hard metal die. If the die shifts slightly during the engraving process, some parts may be stamped more than once.
- Misalignment: This misalignment can occur when the die is improperly aligned, or the engraver accidentally applies pressure to the same area multiple times.
2. Types of Double Die
- Obverse Double Die: This occurs on the front side (the "heads" side) of the coin, where the image of the coin’s face is doubled.
- Reverse Double Die: This happens on the reverse side (the "tails" side) of the coin, where the design on the back is doubled.
- Different Levels of Doubling: The doubling can be strong or weak, with strong doubling being more noticeable.
3. Finding Double Die Coins
- Recognizing the Doubling: Look closely at details such as the lettering, date, and other design features. In double die coins, you can often see enhanced or shadowed lines around letters and images.
- Common Examples: One of the most famous double die coins is the 1955 Lincoln penny, which features noticeable doubling of the date and the word "Liberty." Other notable examples include the 1969-S and 1972 Lincoln pennies.
4. Value
- Market Demand: Double die coins can be quite rare and valuable, particularly those that are well-preserved and exhibit strong doubling. Prices can range from a few dollars for minor examples to several thousand dollars for highly sought-after versions.
- Condition Matters: The condition of the coin (as graded by professional grading services) greatly affects its value, with uncirculated or brilliantly uncirculated specimens fetching higher prices.
5. Collecting and Authentication
- Collectors: Many coin collectors seek out double die pennies as part of their collection.
- Grading Services: It’s advisable to have significant finds authenticated by reputable grading services, as they can properly assess the coin’s quality and authenticity, ensuring it is genuinely a double die and not just a product of wear and tear.
Overall, double die coins like the Lincoln penny are highly sought after in numismatics for their uniqueness and the stories behind their creation.