What are dollar coins made of? The jingle of coins still holds sway even in an increasingly cashless world. But have you ever closely examined a dollar coin and wondered exactly what metals go into making it? If so, you’re not alone!
In short – Modern U.S. dollar coins contain a combination of copper, zinc, manganese, and nickel. However, the specific metal proportions have changed over the years along with dollar coin designs.
Read on as we take a deep dive into the metallurgy behind America’s golden dollars to uncover their origins and composition changes over time.
Basic Metal Composition of U.S. Dollar Coins
Copper is a major component used in the production of U.S. dollar coins. The presidential $1 coins, which were minted between 2007 and 2016, contain 88.5% copper. The more durable copper ensures these dollar coins have a longer lifespan compared to paper banknotes.
In the early 2000s, the U.S. Mint conducted research and concluded that a high copper content was optimal for one-dollar coins. The durability and electrical conductivity provided by copper meant the coins were more cost-effective over the long term despite their higher upfront production costs.
Along with copper, zinc is the other primary metal comprising the current presidential $1 coins. These coins contain 6% zinc which helps make the coins more resistant to corrosion and wear.
Experts say the right balance of copper and zinc offers the ideal mix of durability in mass production. Too much zinc can make the coins too hard and impact the relief and quality of the coin image.
Manganese plays an important role as well in U.S. dollar coins. The presidential dollars contain 3.5% manganese in their metal composition. Adding manganese helps strengthen the coin and prevents unpleasant cracking during the production process.
The U.S. Mint has tested various manganese levels to determine the optimal amount. High levels of manganese negatively impact coin relief and processability.
While nickel is not used in the presidential dollar coins, it remains an important component in other U.S. dollar coinage. The golden dollar coins contain a copper core but are plated with 77% copper, 12% nickel, 7% zinc, and 4% manganese giving them a golden color.
Nickel provides increased durability and a shiny, smooth surface that maintains a nice brilliance to the coin’s appearance over years of circulation and use.
Evolution of Dollar Coin Designs and Metal Contents
Flowing Hair Dollar (1794 – 1795)
The first dollar coins minted in the United States were the Flowing Hair dollars, produced from 1794-1795. These were made of 89.2% silver and 10.8% copper, with a total weight of 26.96 grams. The front featured a profile of Liberty with long, flowing hair, hence the “Flowing Hair” name.
These early dollars are highly sought after by collectors today.
Draped Bust Dollar (1795 – 1804)
Draped Bust dollars succeeded the Flowing Hair design, minted from 1795-1804. The obverse portrait of Liberty was altered to show her with a cap and curly hair, covered by a draped bust. The composition remained 89.2% silver and 10.8% copper.
Several reverse designs were used over the years, with small eagles or Heraldic eagles depicted. These coins are also popular with numismatists.
Seated Liberty Dollar (1840 – 1873)
After a hiatus of over 30 years with no dollar coins minted, the Seated Liberty dollar was produced from 1840-1873. As the name suggests, the obverse featured a full-figure depiction of Liberty in a seated position. The standard 90% silver/10% copper composition was used.
Weights and diameters varied slightly over the years. Many Seated Liberty dollars featured the motto “In God We Trust” starting in 1866.
Trade Dollar (1873 – 1885)
Trade dollars were conceived to facilitate trade with Asia, minted from 1873 to 1885. They weighed 27.22 grams and were made from 90% silver, with the remainder copper. The term “420 Grains”, referring to the silver weight, was added to the reverse.
Unfortunately, trade dollars became problematic in 1876 when their legal tender status was revoked, contributing to their quick demise.
Morgan Dollar (1878 – 1904, 1921)
The most prolific dollar coin issue, Morgan dollars were minted from 1878-1904, and again in 1921. They showed a left-facing bust of Liberty wearing a Phrygian cap, and an eagle reverse. Morgan’s measured 38.1 mm in diameter and weighed 26.73 grams, composed of 90% silver and 10% copper.
Hundreds of millions were minted, and they remain extremely popular with collectors today.
Peace Dollar (1921 – 1935)
Minted from 1921-1935, the Peace Dollar was designed to commemorate the peace after World War I. The obverse featured a radiant Liberty head, and the reverse depicted an eagle at rest clutching an olive branch.
Peace dollars had the same dimensions and metal composition as Morgan’s, with 90% silver and 10% copper. Low mintages of some dates have increased their collectible appeal.
Eisenhower Dollar (1971 – 1978)
The Eisenhower dollar was produced from 1971 to 1978 to commemorate President Dwight D. Eisenhower. These were composed of an outer layer of 75% copper and 25% nickel, with an inner core of 100% copper. Eisenhower dollars measured 38 mm across and weighed 22.68 grams.
Both the obverse and reverse designs featured renditions of Eisenhower.
Susan B. Anthony Dollar (1979 – 1981, 1999)
Minted from 1979-1981, and again in 1999, the Susan B. Anthony dollar honored the women’s suffrage movement leader. These coins maintained their predecessor’s copper/nickel-clad composition. The obverse bore Anthony’s profile, and the reverse depicted an Apollo 11 mission insignia.
Poor public reception hampered its usage, although collectors now seek these out.
Sacagawea Dollar (2000 – Present)
First minted in 2000, the current Sacagawea dollar features Shoshone guide Sacagawea carrying her infant son Jean Baptiste on the obverse. An American eagle graces the reverse. Weighing 8.1 grams with a diameter of 26.5 mm, these coins have a core of 88.5% copper, with the outer cladding composed of 77% copper, 12% zinc, 7% manganese, and 4% nickel.
Millions have been produced annually.
Presidential Dollar (2007 – 2016)
Issued from 2007-2016, the short-lived Presidential dollar series honored past U.S. Presidents in the order they served. The obverse showed bust profiles of the Presidents, with the Statue of Liberty featured on the reverse.
They measured 26.5 mm in diameter and weighed 8.1 grams, sharing the 88.5% copper core/11.5% copper-zinc-manganese-nickel clad composition of the Sacagawea dollar.
Minting Processes for U.S. Dollar Coins
The production of dollar coin planchets starts with long coils of sheet metal alloy being fed into high-speed presses. The alloy used for dollar coins is composed of 88.5% copper, 6% zinc, 3.5% manganese, and 2% nickel.
The presses punch out disc-shaped planchets, which are then mechanically filtered to remove flaws and ensure uniform thickness and weight. The planchets are then annealed to soften the metal.
Collaring and Annealing
After punching, the planchets have slightly ragged edges. These are smoothed and strengthened in a process called “collaring,” which squeezes the perimeter of the coin between two steel collars. The planchets then undergo annealing, where they are heated to over 700°C to soften the metal structure.
This prepares them for the coin-pressing operation. According to the U.S. Mint, approximately 1.2 million dollar coin planchets are produced per day.
The design for each coin is crafted into a die made from tool steel. CNC machines engrave the three-dimensional design into the die face with micrometer precision. Dollar coin dies often carry portraits of presidents on the obverse (heads) side.
An individual dollar coin will go through thousands of impressions before a die is retired.
Dollar coin minting takes place in high-speed coin presses capable of over 750 strokes per minute. The planchets are fed into precision coining presses that apply approximately 55 tons of striking force to imprint the coin design into the metal on both sides simultaneously.
The dollar coins then drop out of the bottom of the press into collection bins. Mistakes and flawed coins are automatically ejected along the way.
Inspection and Bagging
The finished dollar coins proceed through multiple inspection stages where both automated technology and human oversight ensure there are no visible defects. Weight tolerances are also verified to be within very strict levels.
The coins are then counted and sealed into vault bags, each containing 2,000 dollar coins ready for bulk shipment to the Federal Reserve Banks for distribution.
Common Questions About Dollar Coin Composition
Why did the U.S. switch dollar coin compositions over time?
The United States has altered the metal composition of dollar coins over the years to make them more cost-effective to produce while maintaining sufficient durability. According to the U.S. Mint, factors like current metal market prices, production costs, wear characteristics, appearance, and other considerations determine what metals are used.
For example, the early Flowing Hair and Draped Bust dollar coins from the late 1700s were made of 89-90% silver along with 10-11% copper. But the heavy precious metal content made them expensive to mint. So in 1837, the Coinage Act set dollar coin metal composition at 90% silver and 10% copper.
This standard silver blend remained for many decades until silver market prices surged in the mid-20th century.
To offset rising production expenses, Congress authorized a change to an outer layer of 80% silver and 20% copper surrounding a core of 21% silver and 79% copper in 1965 (for Eisenhower dollars). Then in 1971, the Coinage Act transitioned dollars to outer clad layers of 75% copper and 25% nickel around a pure copper core, creating a more affordable coin based mainly on base metals.
How do dollar coin metals impact appearance and durability?
The type of metals used in dollar coins directly affects their look and sturdiness. Those high-in precious metals like silver have an attractive, brilliant luster. The copper content helps strengthen the coin too.
But silver is relatively soft, meaning the dollar can show wear rather quickly with heavy circulation.
In comparison, the current copper and nickel alloy last longer and resist damage better, according to the U.S. Mint. However, some people feel this mix looks cheaper and duller than the gleaming silver dollars of the past. The durability comes at the expense of aesthetics.
What are the pros and cons of various dollar coin metal blends?
|90% silver, 10% copper
|Outer 80% silver, 20% copper + inner 21% silver, 79% copper
|r 75% copper, 25% nickel + 100% copper core
In the end, there are reasonable justifications for altering dollar coin metal compositions over the years even if some changes proved unpopular. The current clad construction offers the most practical blend for an affordable, long-lasting circulating dollar coin.
But many still love the historic, shining silver dollar coins of the past.
What Are Dollar Coins Made Of – Conclusion
As we’ve seen, while dollar coins have represented an important part of American history for centuries, their precise metal compositions have evolved due to shifts in design, minting technology, and metal value.
But across all eras and dollar coin series, the goal has remained the same – creating distinctive and durable coins representing the faith and trust U.S. citizens have not just in their currency, but in the principles upon which America was founded.