Lamination Error

Lamination Error

A lamination error is a flaw in the coin's metal itself, in which part of the surface flakes, peels or breaks away after striking. It originates in the planchet rather than the dies or the press, and appears as cracks, blisters, peeling slivers or small crater-like voids in the coin's surface. Lamination errors are also known as split planchets when the coin separates into layers.

Explanation

Coinage alloys must be homogeneous - the metals fully and evenly mixed - for the planchet to flow smoothly under striking pressure and hold together in circulation. If the alloy melt was poorly mixed, or if impurities such as hydrogen or foreign metal inclusions became trapped in the strip from which planchets are blanked, weak boundaries form within the metal. Striking pressure and subsequent metal fatigue cause the surface layers to separate along these boundaries. Because the flaw is in the raw strip, lamination errors often run in batches when a bad batch of alloy was used.

Identification

Look for raised or sunken cracks that follow the surface, thin peeling flakes of metal still attached at one edge, or cleanly missing areas that expose a rougher inner layer of alloy. A fully split planchet shows two thin halves, each with a granular fracture surface, and weighs roughly half of a normal coin. Lamination flaws frequently occur away from the design's high points and may cross the design without regard to it - a useful distinction from die cracks, which appear as raised lines in consistent positions on many coins from the same die.

Example

On Australian decimal coins, lamination errors most often affect the copper-nickel denominations, appearing as a shallow peeling patch on an otherwise ordinary five, ten or twenty-cent piece. A two-cent or pre-decimal bronze coin with a greenish or scaly surface may indicate corroded impurities rather than true lamination, so composition and colour should always be assessed together.

Important Considerations

• Cause: Lamination is a planchet flaw, not die damage - one coin shows it, while coins from the same dies do not.
• Weight: A split or laminated coin weighs less than standard; a significant weight deficit supports authenticity.
• Value: Small laminations add modest interest, but a complete split planchet or a large detached lamination is a significant and valuable error.
• Confusion: Do not confuse lamination with post-mint corrosion, plating damage on altered coins, or the deliberate peeling of metal to simulate an error.

In summary, a lamination error is the shedding of a coin's own surface along impurity boundaries in the alloy, and its peeling flakes, craters and split halves distinguish it from die-related errors on the same coin's surface.