NGC Error Coins & Mint Varieties

Question 1

What is a 'doubled die' error in numismatics?

Accepted Answer

A coin where the die itself received a doubled impression during the hubbing process, resulting in doubled design elements

Answer

A doubled die error refers to the die—not the coin—receiving a doubled impression during the hub-to-die transfer process, causing all coins struck from that die to show doubled design elements.

Question 2

In numismatics, what is a 'mule' coin?

Accepted Answer

A coin struck with obverse and reverse dies not intended to be used together

Answer

A mule is a coin struck with an obverse and reverse die pairing that was never officially authorized or intended, such as combining dies from two different denominations or designs.

Question 3

What is a 'broadstrike' error coin?

Accepted Answer

A coin struck outside the retaining collar, resulting in a wider and flatter coin

Answer

A broadstrike occurs when a planchet is struck without the retaining collar in place, allowing the metal to spread outward freely and producing a coin that is wider and thinner than normal.

Question 4

What does 'die rotation' refer to in error coin collecting?

Accepted Answer

The angular misalignment between the obverse and reverse dies, measured in degrees

Answer

Die rotation describes how far out of alignment the reverse die is relative to the obverse die, expressed in degrees, with a properly aligned U.S. coin showing 180-degree rotation (coin alignment).

Question 5

A coin struck on a planchet intended for a different denomination is classified as which type of error?

Accepted Answer

A wrong planchet error

Answer

A wrong planchet error specifically describes a coin struck on a planchet manufactured for a different denomination, such as a Roosevelt dime struck on a cent planchet.

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NGC Error Coins & Mint Varieties