Isolated incuse design elements arise from many causes, both inside
and outside the Mint. A 2001-D Lincoln cent sent to me by Gerald
Lykins shows an incuse T (from CENT) in the field to the right of
Lincoln’s face. Lykins wanted to know whether it was a Mint error or
some form of post-strike damage.
The first order of business was to list the various candidates.
(1) Dropped letter: A hardened plug of compacted dirt and
lubricant (“die fill”) falls out of a letter-shaped die recess and
onto a planchet. The letter-shaped plug is driven into the planchet,
leaving an incuse impression (see photo). The impression is normally
oriented (i.e., facing the same way as a normal letter) unless the
plug flips over (see Collectors’ Clearinghouse, April 19 and Aug. 16, 2010).
(2) Brockage from a struck fragment: Stray bits of metal
occasionally find their way between the dies and are struck on one or
both faces. If struck into the next planchet, it leaves an incuse,
mirror-image version of whatever design was present on the fragment
(3) Impression of thin metal layer with uniface strike: If a thin
piece of metal is trapped between a die and a planchet, the strike
will force the metal to mold itself to the die recess. If the fragment
falls out and is struck into the next planchet, it leaves a normally
oriented incuse impression, so long as it (1) doesn’t flip over, and
(2) remains next to the same die (see photo and the Nov. 3, 2008,
(4) Detached lamination flake: A letter-bearing flake can spall
off the surface of a coin and remain behind in the striking chamber.
When it’s struck into a planchet, it leaves an incuse impression that
can be either normally-oriented or mirror-image, depending on the two
factors mentioned above (see photo and Feb. 7, 2005, Collectors’ Clearinghouse).
(5) Accidental contact mark. This can occur inside or outside the
Mint as coins are forced against each other inside machinery.
(6) Intentional alteration. Letters are sometimes intentionally
impressed into a coin, either as a form of mindless vandalism or to
make a quick buck.
Since the T on Lykin’s cent is symmetrical around a vertical axis,
there is no way to tell whether it’s normally oriented or
mirror-image. It would also have been helpful if the letter had
overlapped some of the design. Still, many useful clues remain that
allow us to tease apart the various possibilities.
A dropped letter is unlikely, as most are found on the same face
as their normal raised counterpart. Here the letter is found on the
A shallow depression constituting the corner of a rectangle is
located above and to the right of the T. The floor of the depression
shows no texture. While dropped fillings can extend beyond the letter
itself, the resulting shallow depression is irregular in outline and
often shows a coarse texture.
The incuse T is clearly not a brockage from a struck fragment. The
letter impression and the surrounding recess are both too shallow. The
borders of the recess are too uniform and too incomplete. While a
brockage of this type will usually be found on the face opposite its
normal raised counterpart, it will also usually be aligned with it in
vertical space. The incuse T is not aligned with the raised T of CENT.
A detached lamination flake from a struck coin is unlikely to
leave a surrounding recess that is incomplete, rectangular in shape,
and devoid of texture.
An incuse impression from a thin, struck fragment is unlikely for
the same reasons. The outline of the letter also tends to be mushier
and the letter is usually found on the same face as its raised
counterpart (see photo).
The evidence indicates this is not a Mint error. That leaves
either an accidental contact mark or an intentional alteration.
An accidental contact mark is unlikely. The field to the right of
Lincoln’s face is recessed and sheltered — the last place an isolated
contact mark would be expected. Light contact marks are generally
restricted to the higher points of the design.
The preponderance of the evidence indicates that this isolated T
represents an act of mischief. I believe that the perpetrator used a
cutting disc attached to a Dremel-type rotary tool to cut out a small
rectangular piece from a cent. The piece was then placed on the
obverse field and squeezed against the Lykin’s cent in a vise or C-clamp.
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