1972-D Floating Die Clash FDC-1C-1972D-01

Description

Cataloged as FDC-1c-1972D-01, this 1972-D Lincoln Memorial cent reverse hosts the first documented "exogenous floating die clash" in numismatic literature — a die fragment originating from a completely different striking chamber or from a previously-installed die that became lodged in the press and was driven into the active reverse die at an angle. Discovered by Bob Piazza, this groundbreaking variety was analyzed by noted error coin researcher Mike Diamond, who explained that the reverse die carries the impression of what was probably a die fragment derived from another striking chamber or from a previously-installed die. In the latter scenario, the die fragment would most likely have lodged in a die recess before falling out after a new die was installed. The fragment was driven into the reverse die at an angle, generating an impression of the peripheral field and the top of two incuse letters — elements that do not match any portion of the obverse die that struck this coin. This non-matching characteristic is the defining diagnostic: because the clash mark cannot be reconciled with the paired obverse die, it must have originated from an external source — hence Diamond's designation as "exogenous." As Diamond noted, this is the first exogenous floating die clash documented in numismatics, distinguishing it from standard floating die clashes where a fragment calves from one of the two dies currently installed in the striking chamber. The fragment-at-angle geometry explains why the transferred impression shows peripheral field characteristics and partial letter forms rather than a centered design transfer — the fragment struck the die surface obliquely, impressing only a portion of whatever design it carried. The MadDieClashes attribution team cataloged this variety, recognizing its significance as an entirely new mechanism of die damage that expanded the taxonomy of clash-type errors beyond the previously understood categories.

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