I don't know why people keep calling coins with die cracks "errors". They are nothing more than coins struck on worn dies. Chris
I think it's technically a variety and not a mint error since several varieties of die cracks, like the Speared Bison, have been discovered that are exactly alike. Since this is a die issue or accidental modification from stress then it becomes a variety. But I don't think "all" die cracks are varieties.
CudsOnCoins has eleven examples of 'spikeheads' for the 1991, they don't appear to have your example.
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