Part IV. Die Errors:

Die Cracks:

Bilateral, Radial, Antipodal Die Cracks

Definition: Radial die cracks that develop at opposite poles and converge toward the center of the die face.  These are often mistaken for split dies.  The difference is that these cracks do not meet in the center.  Distinguishing between radial antipodal die cracks and split dies is made difficult by the frequent occurrence of a central zone of subsidence in both types of errors.  In other words, the die face tends to sink in and the design becomes unclear or non-existent within the zone of subsidence.

The reverse face of this 1974-D nickel shown above has a pair of radial, antipodal die cracks.  These cracks fail to meet in the center of the design and are not aligned with each other.  Although there is a die subsidence error in the center of the die face, the central design remains clear enough to establish that no crack crosses it from one end to the other.  The crack extending in from the left side peters out as it enters the top of Monticello’s staircase.  The crack that extends in from the right pinches out as it meets the column on the right.

Part V: Planchet Errors:

Blanking and Cutting Errors:

Definition: Any error that can be traced back to 1) the blanking press, 2) the shears, saw, or guillotine that trims the ends of the coin metal strip, or 3) the splitter that divides the coil of coin metal into narrower strips.

Special Note on clipped coins;

Because this sub-section of the Error-Variety Ready Reference is dedicated to “clipped” error coins, it is worth mentioning several diagnostics useful for distinguishing the genuine article from a tampered coin:

1. Blakesely effect. This can potentially develop on any coin struck on a blank whose circular outline is interrupted for any reason, provided that the interruption appeared before the blank entered the upset mill.

The Blakesley effect is located at the pole opposite the deficit. It consists of 1) weakness or absence of the design rim combined with, 2) an especially well-struck edge.

The Blakesley effect reflects the fact that this area of the planchet was never upset. The deficit at the opposite pole prevents the upsetting mill from squeezing the planchet at this point and pushing up a proto-rim.

The Blakesley effect is not always present, especially when the deficit is very large. In the latter case, effective striking pressure is high enough to cause coin metal to completely fill the rim gutter of the die. Effective striking pressure is increased because the entire tonnage of the strike is concentrated on a piece of metal whose area is substantially smaller than a normal planchet.

2. Fade-out and taper of the design rim as it approaches the clip (most clip types will have this feature).

3. “Cut-and-tear texture” on the exposed edge of the clip. Only curved clips and elliptical clips will have this feature. It is also referred to as a “breakaway zone” or a “belly line”. The cut-and-tear texture refers to the microscopic texture of the clipped edge. Part of it is smooth, while part of it is grainy. The grainy part tells you that this was the original bottom of the coin metal strip. As the blanking die (punch) penetrates the coin metal strip, it forces a blank through a hole in a perforated base plate. The sharp, right-angle edge of the blanking die slices through the upper part of the coin metal strip. The lower part of the blank simply tears away from its hole in the coin metal strip as it is pushed down by the flat face of the blanking die.

4. Reversal of position of exposed copper core. This pertains only to curved and elliptical clips in clad issues. In a clad coin, the copper core is asymmetrically exposed along the edge. The position of the exposed copper core “flips” when you transition from a normal edge to the clipped edge. The reason is simple: the normal edge represents the edge of the blank, while the clipped edge represents the edge of the hole.

As the blanking die pushes a blank through the hole in the perforated base plate, the edge of that hole drags the bottom clad layer onto the edge of the blank for a short distance, partly hiding the lower portion of the copper core. Simultaneously, the edge of the blanking die forces some of the top clad layer down onto the edge of the hole in the coin metal strip, partly hiding the upper part of the copper core.

5. Metal flow in design elements bordering the deficit. Metal flow refers to a distortion and stretching-out of letters, numbers, and any other raised feature. It is caused by coin metal “squirting out” beneath the dies.

6. Proper curvature for the type of clip. Be aware that striking pressure and the expansion of the coin can alter the shape of a clip, sometimes drastically. This is especially true if clip is large and if the coin is struck out-of-collar.

PART V. Planchet Errors

Plating blisters

Definition: This error type occurs only on copper-plated zinc cents from 1982 to the present. Blisters form during the strike when expanding gas pushes up the copper plating from heat and pressure. A weak bond between the copper plating and the zinc core is a necessary prerequisite as are contaminants within or under the plating.

Below is a 1992 Lincoln cent with circular plating blisters. The largest blister is oblong and irregular, it runs through Lincoln’s coat into the field and below the date.

Illustration by J. Cuvelier

PART II. Die Varieties:

The images below show a multitude of 1996-P Lincoln cents that have been bonded or fused together. This particular error was caused by a die cap forming on the hammer die. As a planchet was feed into the striking chamber, the hammer die would make contact with the planchet and fuse it into the mass. This particular “pile-up” of coins is refered to as a “pine cone” since it does resemble that object.

This error comes to us from Mark Lighterman.

PART VI. Striking Errors:

Bonded coins

Images are courtesy of Heritage Auctions.

This 1999 Lincoln cent started out as broadstrike with a full, centered, first-strike brockage of the reverse design on the obverse face.  Several other planchets were subsequently fed on top of it and fused to it by the pressure of the strikes.  The reverse face of this bonded assemblage also struck at least one planchet, but did not fuse to it.

Part V: Planchet Errors:

Plating Errors

Brassy Plating

Definition: brassy plated cents are the product of a zinc contamination within the copper plating bath. The presence of the zinc produces a plating that has a slightly yellowish appearance compared with the normal copper with a red, orange or pinkish appearance. The zinc contamination comes from trapped zinc planchets that are  retained and ultimately dissolved in the plating bath. They are often found on 1983 and 1998 Lincoln cents, but could hypothetically be found on any year plated planchets were used.

Below to the left is a 1998 Lincoln cent with a brassy plating. For a color comparison a normal 1988-D Lincoln cent is adjacent.

Illustration by J Cuvelier

PART VI. Striking Errors:

Broadstrike:

Cupped

Definition: A broadstrike is a coin that is struck out-of-collar and in which the design is complete on both faces.  Most broadstrikes expand in the horizontal plane, but some will show cupping.  Cupping can affect the entire perimeter of the coin or only part of the perimeter.  Cupping is almost always toward the hammer die.

The 1999 cent shown above developed an almost vertical wall as it curled toward the obverse (hammer) die.  A corona of exposed zinc formed at the perimeter of the design on both faces.

PART VI. Striking Errors:

Broadstrikes

Definition:A coin that is struck outside the collar.  The collar is the retaining ring that establishes the final diameter of the newly-struck coin.  A broadstrike will expand beyond the diameter of a normal coin, sometimes drastically so.

A perfectly centered coin that is struck out-of-collar is simply called a “broadstrike”.  An imperfectly centered coin that is struck out-of-collar is called an “uncentered broadstrike”.

In order to qualify as a broadstrike, the full design must be present on both faces.  If the design is cut off on either face, it is called an “off-center strike”.

The images below show a 1916-D Lincoln cent that has assumed the form of an uncentered broadstrike.

Images are courtesy of Heritage Auctions.

The images below show a broadstruck 1997-(?) Washington dollar coin.  Due to its enlarged diameter, this dollar coin did not receive the edge inscriptions.