Pennies have an interesting history when it comes to their metal composition. While they were originally made entirely of copper, rising copper prices led the U.S. Mint to start experimenting with alternative metal compositions in the early 1980s. This eventually resulted in the zinc-coated steel pennies that are still in circulation today.
When were pennies first made of copper?
Pennies have been made of copper for most of their history. The first official one-cent coin produced by the U.S. Mint in 1793 was 100% copper. This remained the case for nearly 200 years, with pennies containing a copper composition of 95% from 1837 onward.
When did pennies start changing composition?
In the early 1980s, the price of copper started rising dramatically on global markets. Given that the face value of a penny was less than the market value of its copper content, the U.S. Mint decided to experiment with alternative metal compositions to save on material costs.
This led to the following key dates:
- 1982 – 95% copper was reduced to 97.6% zinc and 2.4% copper (copper-plated zinc). This change was visible, as the coins had a different color.
- 1983 – The coin composition was changed again to 97.5% zinc and 2.5% copper to improve manufacturing efficiency. This resulted in a similar appearance to the pre-1982 copper pennies.
When did pennies become zinc with a copper coating?
The big change came in 1982, when the majority of the penny’s composition was switched to zinc with a thin copper coating. However, this was not initially intended to be a permanent change.
The initial plan was to change the metal content temporarily while copper prices were high, and then switch back to a 95% copper composition once prices stabilized. But by 1985, it became clear that copper prices would remain elevated in the long-term.
As a result, in 1985 the U.S. Mint decided to make the 97.5% zinc composition permanent going forward. So while 1982 was the first year pennies contained zinc, 1985 was the year this composition became permanent.
When did the Lincoln Memorial cent design change?
An interesting side note is that in addition to the metal composition change, 1982 also saw a change in the penny’s design on the reverse (tails) side. Prior to 1982, the reverse featured the Lincoln Memorial design by Victor David Brenner that had been in use since 1959.
In 1982, this long-running Lincoln Memorial design was replaced with a new commemorative design by Frank Gasparro, marking the 100th anniversary of Lincoln’s birth. This new reverse design featuring Lincoln’s birth and early childhood was used for pennies minted from 1982-2008.
In 2009, for Lincoln’s bicentennial, the reverse was changed back to Brenner’s original 1959 Lincoln Memorial design, which is still in use today.
What is the copper coating thickness on current pennies?
Modern pennies contain 2.5% copper plating over a zinc core. The thickness of the copper coating is approximately 0.05 mm, or about twice the thickness of a human hair.
This thin layer of copper provides the distinctive penny color and protects the zinc core from corrosion. The thickness is carefully controlled during the minting process to keep costs low while maintaining the visual appeal of a copper coin.
Why are pennies still copper-colored if they are mostly zinc?
The reason modern pennies still appear copper-colored is because of their thin copper coating. Copper has a distinctive reddish-orange tone that visually dominates over the gray color of zinc.
A penny’s color comes from its surface reflectivity, not its internal composition. So even a very thin copper layer is enough to maintain the traditional coppery hue of pennies when light bounces off the coin’s surface.
The zinc core does affect the coin’s appearance slightly, giving it a lighter color compared to the deeper brown tones of pure copper pennies. But the overall effect remains a coppery penny color.
Conclusion
While pennies were traditionally made from 95% copper for most of their history, rising copper prices in the early 1980s led the U.S. Mint to switch compositions. This resulted in the current zinc core with copper coating that has been used since 1985.
So 1982 marked the first year of transition, with pennies changing from mostly copper to zinc with a copper coating. But it was the decision in 1985 to make this change permanent going forward that solidified the new metal composition for pennies moving forward.
