What it is
Clad dimes, quarters and halves have copper-nickel layers bonded to a copper core. If one layer separates before striking, one side of the coin shows copper color.
What causes it
The bonded layer peeled off the strip or blank before striking.
How to identify it
- One side looks copper colored with the design struck into it.
- The coin weighs less than normal.
- The design on the copper side is softer.
How to tell it from damage
Coins dipped in acid or chemicals can strip the outer layer. Weight and the sharpness of the strike help tell them apart.
How clad strip is made and where the layer fails
The Mint introduced clad coinage in 1965 for dimes and quarters and in 1971 for copper-nickel half dollars and the new dollar. Clad strip is made by bonding sheets of copper-nickel, 75% copper and 25% nickel, to both sides of a pure copper core under heavy pressure, then rolling the layered sheet to coin thickness. Where the bond is weak, perhaps from dirt, oxide or uneven pressure, an outer layer can separate from the core.
If the outer layer falls away from a blank before striking, the blank has a copper face and the coin is struck that way. If it peels off after striking, the coin loses its finished design on that side. Both are called missing clad layer errors, but the timing makes a large difference to how the coin looks.
The same error occurs on the 40% silver half dollars of 1965 to 1970, which used outer layers of 80% silver over a core of about 21% silver. It also occurs on Sacagawea and Presidential dollars, which have manganese brass outer layers over a copper core. On those dollars, a missing layer shows a pinkish copper face beside a golden one.
Partial and complete missing layers
Specialists split these errors by how much is gone. A complete missing clad layer takes away the whole outer layer on one side. A partial missing layer, also called a clad layer peel or delaminated clad layer, shows a patch of copper core where part of the layer lifted, with the rest still in place. A retained clad layer has separated but still clings to the coin, often bent or cracked.
Rarer still are coins struck on a core with both outer layers missing, which come out entirely copper colored and much lighter. These are sometimes mistaken for coins struck on a cent planchet, but their diameter and weight do not match a cent blank.
What the copper side looks like
When the layer was gone before the strike, the copper side shows the design struck into the core, but it is usually softer and less detailed than on a normal coin. The blank is thinner than normal, so there is less metal to fill the dies and the high points and rim may be weak. The copper side is bright copper red on a fresh coin and tones to brown with time.
When the layer peeled after the strike, the exposed core shows only a ghost of the design or none at all, because the design was struck into the outer layer above it. The edges of the remaining layer around a partial peel are sharp and may be slightly raised where they lifted.
Checking the edge and the weight
The edge is the quickest diagnostic. A normal clad coin shows a copper stripe running around the middle of its edge, with silver-colored bands on both sides. A coin missing one layer shows the copper stripe running all the way to one face, with a silver band on only one side. Check the edge under a loupe all the way around.
Then weigh the coin. Each outer layer is a meaningful share of the coin's weight, so a coin missing a full layer is clearly underweight. A clad quarter normally weighs 5.67 grams and a clad dime 2.268 grams. If a copper-colored coin weighs the normal amount, something other than a missing layer is going on, most likely plating or a chemical effect.
Why chemical stripping is not the same error
Chemically treated coins are the main fakes. Coins soaked in acids or other chemicals can lose their outer surface and show copper underneath. But chemicals attack both sides and the edge at once, leaving pitted, grainy or frosted surfaces with rounded, eroded design details. The coin loses weight unevenly and the copper stripe on the edge looks ragged.
A coin missing its layer before the strike shows smooth, struck surfaces on the copper side, with flow lines, while the other side is untouched. The copper side was formed under the dies, so its design edges are crisp even when shallow. Chemical stripping can only soften what was already there.
Copper-plated clad coins are another mimic. Plating adds a little weight rather than removing it, covers the edge stripe and often shows bubbles or thin spots at the rim.
How missing clad layer errors are graded
Grading services list these as a missing clad layer on the obverse or reverse, or as a clad layer peel, with partial errors described as such. A complete layer missing before the strike on a quarter, half dollar or dollar coin draws the most interest, because the copper face with a clear design is so striking.
Frequently asked questions
What causes a missing clad layer?
The bonded layer peeled off the strip or blank before striking.
How can I tell a missing clad layer from damage?
Coins dipped in acid or chemicals can strip the outer layer. Weight and the sharpness of the strike help tell them apart.
Why is one side of my quarter copper colored?
It may be a missing clad layer error, where the copper-nickel outer layer separated from the copper core. Check the edge for a copper stripe that runs to one face and weigh the coin, which should be light.
How much does a quarter missing a clad layer weigh?
It weighs noticeably less than the normal 5.67 grams because one outer layer is gone. A copper-colored quarter at full weight is more likely plated or altered.
Is a missing clad layer the same as a lamination error?
They are related but not the same. A missing clad layer is a failure of the bond between the layers of a clad coin, while a lamination is a flaw inside a single metal.