Comprehensive Error-Variety Checklist

Submitted by JonSullivan on Sat, 05/30/2015 - 13:52

Comprehensive Error-Variety Checklist


Compiled by Mike Diamond



This checklist is my attempt to compile a comprehensive listing of all known variety and error types, subtypes, and associated effects.

            While the traditional planchet-die-striking method of classification hasn't been completely abandoned, it has been absorbed into a much more detailed and precise taxonomy. This is intended to reflect the numerous steps (and missteps) in the minting process that generate the great diversity of anomalies presented here.

            Many of the categories will be familiar to veteran collectors. Others will perhaps be dimly recalled, while others will be unfamiliar. Many of the more obscure error types have been treated in detail in articles published in Errorscope. These articles are referenced next to the appropriate entry (“ES”).   Other treatments can be found in Coin World (“CW”).

            I have tried to restrict this checklist to basic error/variety types and subtypes. Combination errors have been kept to a minimum. Had I attempted to incorporate all conceivable two-error combinations, this would have generated almost half a million entries. That would have been both unwieldy and unnecessary.

            This checklist is a continually evolving project. The ultimate goal is to use this checklist as the nucleus for a massive encyclopedia.



CW=Coin World

Part I. Design Subtypes


Patterns and Prototypes (accidental release)


        1916 Winged Liberty (“Mercury”) dime patterns

        1971-S Eisenhower dollar prototype (CW 9/29/08)

        2000-P Sacagawea “Cheerios” dollar


Design execution errors


       1817 large cent with 15 stars

       1828 half cent with 12 stars


Mid-year design modification


       Type 1 and Type 2 1913 “buffalo” nickels (raised vs. recessed “FIVE CENTS”)

       1917 Standing Liberty quarter with breast covered or uncovered

       Change from 1960 small date to large date cent

       1853 Seated Liberty dimes and half-dimes, with and without arrows


Conceptual design flaw (foul-up in design or in translating design to master hub or master die)


       Misspellings (foreign only)

       Inaccurate design

            Italy 1000 Lire with outdated map borders

            Canadian $5 Olympic Coin.    Runner with two left feet




Unauthorized strikes and unauthorized issues (CW 1/20/14)


       1913 Liberty Head Nickel

       1954 Mexico 5 centavos (small size)



Part II. Die Varieties


Reduction lathe doubling (master hub doubling)


Master die doubling (master die with a doubled die variety)


Broken hub (chipped hub) (CW 12/23/13)


Hubbed-in debris (CW 5/27/13)


Broken punch


Longacre doubling


Doubled dies (incl. tripled dies, etc.)


       Rotated hub doubling (Class I)

            1872 Seated Liberty dime with 175 degree rotation (ES July/August 2003; CW 2/10/03)

       Distorted hub doubling (Class II)

       Design hub doubling (Class III)

       Offset hub doubling (Class IV)

       Pivoted hub doubling (Class V)

       Distended hub doubling (Class VI)

       Modified hub doubling (Class VII)

       Tilted hub doubling (Class VIII)


       Single-squeeze doubled dies (often attributed to Class VIII) (CW 2/14/05, 9/12/05)

            Peripheral doubling (CW 8/2/04)

            Centrally-located doubling


       Weaker impression hubbed last (e.g. 1963-D cent) (CW 6/14/10)


Weak hubbing


Incomplete hubbing


Tilted hubbing


Repunched date (ES July/August 2012; CW 12/14/09)


       1956-D cent with repunched 5 (controversial) (CW 9/20/04, 7/16/12)

       1957-D cent with repunched 7 (controversial)


Re-engraved date (on master die or working die)


Blundered date

Misplaced date (e.g. digits in denticles) (CW 4/21/03)


Misplaced mintmark


Phantom mintmark (working hub has mintmark incompletely removed)

       (e.g. faint D and S mintmarks in cents from the late 1990s)


Dual mintmark


       1980 D & S cent (recently delisted)

       1956 D & S cent (controversial)


Inverted mintmark


Horizontal mintmark (inevitably repunched)


Tilted mintmark (punched-in at an angle) (CW 7/28/14)


Rotated mintmark (CW 7/28/14)


Repunched mintmark


       Overlapping mintmarks        

       Mintmarks totally separated

       Two different fonts

       Large over small mintmark


Deeply-punched mintmark (CW 9/29/14)


Weakly-punched mintmark


Overmintmark (e.g. 1944-D/S cent)


Other repunched or re-engraved design elements




       Assay value


Omitted mintmark (e.g. 1982 no-P dime)


Omitted date (foreign only) (CW 4/28/14)


Other omitted design elements


Large and small mintmark varieties


Different mintmark styles




       Caused by repunching

       Caused by second hubbing with die of different date (Class III doubled die)


Dual Date (earlier date faint)

       Caused by erasing earlier date on working hub

       Caused by removing earlier date from working die and re-hubbing

       (e.g. 1975 Bahamas 5c with faint date “1973” on opposite face)


Wrong date


       Date later than final date of issue (e.g. 1913 Liberty Head nickel)

       Date earlier than first date of issue (e.g. 1954 Mexico 5 centavos - small size)

       Wrong digits (e.g., 1393/1893 Peruvian peso)

       Transposed digits


Blundered die (various types) (CW 8/18/08)


Special Finish Errors (Proofs, Mint Sets, Special Mint Sets, Satin Finish, etc.)


       Frosting slop-over (proofs) (CW 2/21/11)

       Offset frosting (proofs) (CW 2/21/11)

       Design removed by proof polishing (CW 2/21/11)

       Field lowered by proof polishing (CW 2/14/11)

       Frosting in wrong place (CW 2/28/11)

            “Frosted Freedom” $50 and $100 platinum coins (CW 8/1/11)

       Frosting omitted

       Stencil outlines (CW 2/18/13)


Design Extension Dimples (CW 4/18/2011)


Edge lettering font variants

       Presidential dollars (4-5 types) (CW 10/18/10)




Part III. Die Installation Errors


Mules (ES May/June 2010)


       Wrong hammer die

            1995 cent/dime mule

       Wrong anvil die

            1993-D and 1999 cent dime mules

       Wrong hammer and anvil die

            Maryland quarter on Sac planchet in Sac collar (3 specimens)

       Two anvil dies

            Two-tailed clad dime (1 known specimen, probably from 1965)

            Two-tailed clad quarter (2-3 known specimens, probably from 1965)

            1982 Jamaica cent with two obverse faces

       Two hammer dies

            1859 Indian cent with two obverse faces (unique)

       Two different countries

            (1967) Bahamas 5c/New Zealand 2c mule

       Different denominations

            Washington 25c/Sacagawea $1 mules (13 specimens, 3 die pairs)

       Mule die larger than normal die and collar

            1995 cent/dime mule

       Mule die same size or smaller than normal dies and collar

            (All known U.S. mules employ dies of different sizes)

        Temporal mule (dies from different years) (CW 1/20/14)

            1959-D wheatback cent (unique)

            2000 Macedonia 1 denar muled with obverse die used in prior and later yers

            Commemorative 1992 Canadian quarter muled with 1993 reverse (CW 9/17/01)

       Temporal/transitional mule (dies from different years with change in planchet composition) (CW 1/20/14)

            1942-S Cu-Ni five cent coin with small S-mintmark to right of Monticello (unique)

            1993 bimetallic Russia 50 roubles (St. Petersburg mint set only) (ES March/April 2010)

       Regular-issue die muled with commemorative die

            September and November 1999 Canadian quarters

       Regular-issue die muled with government medal or token die

            2000 Canada “map mule”

       Regular-issue die muled with private token, medal, or nonsense die (CW 11/25/13)

       Mules involving pattern dies (various types)

            Normal die paired with pattern or prototype die (CW 2/2/04)

       Coin die matched with private token die (ES Jan/Feb 2008)

       Collar mule (collar from different denomination of same or similar size installed)

       Lettering die mule (mismatch between edge lettering applied before or after strike and the design shown on the obverse and reverse face)

                        Presidential dollar with wrong date on edge

                  2009 Zachary Taylor dollar with 2010-D edge inscription (CW 2/22/10, 3/1/10)

            2007-D Sacagawea dollar with Presidential dollar edge lettering (CW 7/9/12)

       Pseudo-mules (3 pathways) (CW 4/25/11, 3/19/12, 4/23/12)

            One U.S. two-tailed quarter may belong in this group (CW 11/27/04; 8/27/12))


Mismatched business / unfinished proof dies


       1999 $5 and $10 gold eagles struck with unfinished proof dies (W-mintmark)

       1998-2000 business strike cents with proof-style reverse (“wide AM”)

       1998-S and 1999-S proof cents with business-style reverse (“close AM”)

       1956 -1964 quarters with “Type B” proof reverse


Finished proof die matched with business die


       Early 19th century examples (CW 8/20/12)


Transitional reverse dies (minor temporal mismatch or “mini mule”) e.g.:


       1939 nickel with reverse of 1938

       1940 nickel with reverse of 1939

       Proof 1940 nickel with reverse of 1938 (CW 4/19/08)

       1964-D quarter with the “Type C” reverse of 1965

       1988 cent with reverse of 1989

       1992-D cent with “close AM” reverse


Inverted die installation (not an error) (CW 2/15/10)


       Older issues struck with inverted dies (e.g. buffalo nickels and Mercury dimes)

       Recent installation of inverted dies (beginning 1992)

       Saddle strikes produced by inverted dies


Fixed rotated die errors (see Part VI)


Collar installation error


       Smooth edge instead of reeded edge (and vice versa)

            1863 Indian cent with reeded edge (CW 6/3/2002)

       Smooth edge instead of edge design (and vice versa)

       Reeded edge instead of edge design (and vice versa)

       Segmented proof collar with segments out-of-order (CW 4/7/08)

            2007-S proof Presidential dollar with segments arranged in incorrect sequence (CW 4/7/08)


Use of flat, featureless dies (CW 6/30/14)


Use of cancelled and defaced dies (CW 5/12/14)



Part IV.  Die Errors



Reeding vs. no reeding varieties (foreign only)


Concentric lathe marks (ES Nov/Dec 2003)


       Especially common among 1996-D cents


Rusted die (CW 12/1/08)


Excessively deep rim gutters


       1991 cents


Rockwell test mark left in die (bump seen on coin) (ES July/Aug 2006)


Collar manufacturing errors


       Wide collar (ES Nov/Dec 2002; CW 5/17/10)

            Created by improper machining or improperly machined broach

            Created by use of wrong broach

            Improper use of correct broach

            Widening due to wear

            Widening due to 3 or more vertical collar cracks and associated expansion (CW 5/17/10)

       Abnormal reeding, e.g:

            1921 Morgan dollar with infrequent reeding

            1924-D Mercury dime with infrequent reeding

            Low, narrow reeds caused by truncation of ridges on collar face (ES March/April 2010; CW 1/25/10, 4/16/12)

                  1964-D 25c

                  2008-P New Mexico 25c





Hub Retouching


       Channeling (Hub retouching affecting master and working hubs from 1920s to 1940s) (CW 7/23/12)



Die retouching


       Re-engraved “AW” mintmark on 1944-D half dollar (CW 2/2/04, 2/16/04, 3/1/04)

       Re-engraved front of Lincoln's coat (1953 proof cent)

           1938 proof nickels with re-engraved letters and design details (ES Jan/Feb 2009)


Die damage (ES, Nov/Dec 2004, Jan/Feb 2003; CW 5/21/12)


       Die dents (ES, Nov/Dec 2004, July/August 2005, Nov/Dec 2005; CW 9/15/03, 12/22/14)

       Die scrapes (CW 4/23/07)

       Accidental die scratches

       Die gouge

       Impact scar

       Accidental die abrasion (CW 9/8/14)

       Intentional die abrasion ("die polishing") (CW 3/29/10, 5/31/10, 9/8/14)

            Heavy die scratches

            Thinning and loss of design elements

            Abrasion affecting entire die face

            Localized abrasion

       Over-polished proof and SMS dies (CW 2/21/2011)

       Localized removal of field from proof polishing (CW 2/14/2011)

       Peripheral die damage (ES March/April 2005)

            Die attrition errors (ES May/June 2003, March/April 2005, March/April 2009; CW 1/4/10, 12/24/12, 4/14/14)

       Catastrophic die damage (ES March/April 2002; CW 9/15/03, 9/19/11, 10/27/14)

       Cancelled or defaced dies (foreign only)

            1994 Hong Kong bimetallic 10 dollars

            Egypt 25 piastres struck by defaced 50 piastres dies (CW 5/12/14)


Hubbing-induced die deformation


       Wavy steps (Lincoln cents only) (ES July/Aug 2006, Nov/Dec 2006)

       Trails (ES Sept/Oct 2006,  Nov/Dec 2006, Jan/Feb 2011; CW 3/8/10)


Hubbed-In debris


Collar damage (ES March/April 2010; CW 1/25/10, 4/16/12)


Clashed dies (ES March/April 2002; CW 3/22/10, 4/30/12)


       Chatter clash (multiple staggered clash marks) (CW 6/25/12)

       Multiple clash marks

       Raised clash marks (CW 8/11/14)

       Double clash with reciprocal counterclash (Type 1) (ES Nov/Dec 2004; CW 12/13/10)

       Misaligned die clashes (ES May/June 2004, July/August 2004; CW 6/25/12)

            Horizontally misaligned die clash

            Vertically misaligned (tilted) die clash (CW 1/3/11, 5/9/11)

            Pivoted die clash

            Radically misaligned, rotated, pivoted clashes – produced at installation? (CW 7/12/10, 12/31/12)

            Rotated die clash

            Combination clashes

       Mule clash errors, e.g. (ES, July/August 2002) (CW 11/17/08)

            1864 2c reverse die clashed with Indian cent obverse die

            1857 1c obverse die clashed with Seated Liberty 50c  obverse die

            1857 1c obverse die clashed with Seated Liberty 25c reverse die

            1857 1c obverse die clashed with Liberty $20 obverse die

            1870 Shield nickel obverse clashed with Indian Head cent obverse

       Floating die clash (collision with die fragments) (ES, May/June 2002, May/June 2005; CW 7/19/10)


Collar clash (CW 6/11/07)


       Hammer die

       Anvil die (uncommon)


Die damage with design transfer


       Floating die clash (ES, May/June 2002, May/June 2005; CW 7/19/10)

       Type 2 counterclash (ES, May/June 2002, July/August 2002, Sept/Oct 2002, Jan/Feb 2009, Sept/Oct 2010) (CW 9/29/08, 12/13/10, 4/9/12, 4/21/14)

       Miscellaneous and unexplained forms of design transfer/duplication

            Some presumed Canadian counterclashes may prove to be something else


Die deterioration/deformation errors


       Severe die wear

            Radial flow lines

            Concentric flow lines (uncommon)

            “Orange peel” effect

            Thinned (instead of thickened) letters and numbers (CW 8/28/13)

       Die deterioration doubling (CW 9/10/12)


            Incuse (uncommon) (CW 2/4/08)

       "Blebs" or “patches” of die erosion (ES July/Aug 1998; CW 7/21/03)

       Progressive, indirect design transfer (“internal metal displacement phenomenon”, “ghosting”) (CW 6/7/10)

            Common in 1946-S and 1948-S cents

       Soft die error (ES July/Aug 2001, Nov/Dec 2001) (CW 9/17/12)

            (premature, localized, exaggerated, and peculiar patterns of deformation)

            e.g., 1943-S  “goiter neck” quarter

       “Ridge rings” on copper-plated zinc cents (CW 2/14/05, 2/28/05)

       Well-defined rings on world coins (ES Sept/Oct 2006) (CW 2/17/14, 11/10/14)

       Die subsidence (sunken die error) (ES July/August 2004, Nov/Dec 2004; CW 6/2/03, 11/29/04 3/12/12)

            e.g., 1924-S   “goiter” cent

            Co-occurring with split die

            Co-occurring with bilateral, radial, antipodal die cracks (CW, 6/20/11)

            1988-P nickels with lump on head (CW 4/4/11)

            Massive die collapse in 2003-D dime (ES Nov/Dec 2011; CW 8/29/11)

            Paralleling and flanking die cracks (CW 8/12/13)

            Recurring die subsidence error (CW 4/4/11, 3/31/14)

       Design creep

            Reverse (hammer) 2014-P nickel die (CW 4/13/15)

            In fractional Euro coins

       Peripheral die expansion and erosion (CW 8/13/12, CW 4/13/15)

       “Starburst” pattern of radial streaks on Sacagawea dollars (cause uncertain) (CW 8/15/05, 11/7/05)

       Reciprocally deformed, convexo-concavo dies

            Centrally-located deformation; 2001-P 50c) (ES Sept/Oct 2008; CW 1/19/15)

            Peripherally-located deformation; India 2 rupees (CW 1/19/15)




Die breaks


       Cuds (CW 10/17/11)

            Ovoid cuds

            Irregular cuds

            Crescentic cud (ES March/April 2005)

            Circumferential cuds (ES March/April 2005)

            Elongate cuds (CW 12/8/14)d

            Rim-to-rim cud (ES May/June 2003)

            On off-center or broadstruck coins (CW 9/12/11)

       Retained Cud (ES Jan/Feb 2006; CW 4/17/06, 7/24/06, 1/24/11)

            Anvil die

            Hammer die (doubtful) (CW 8/8/13)

                    Cud sinks in

                    Cud protrudes beyond die face (rare)

            With vertical displacement

            With horizontal offset

            With lateral spread

       Interior (internal) die break (ES May/June 2003; CW 10/25/10)

            Connected to die cracks or splits

            Freestanding (ES May/June 2005)

       Retained interior die break (ES July/August 2004)        

            Connected to die crack or split die


       Rim cud

       Die chip

       Catastrophic die failure (ES May/June 2007) (CW 5/20/13)

       Spontaneous break

       Break produced by impact


Collar breaks (collar cuds) (ES May/June 2008; CW 5/17/10, 11/22/10)


       Complete collar break (abrupt loss of entire arc segment)

       Irregular collar break

       Chipped collar

       Vertical collar crack

       Horizontal collar crack (theoretical only)

       Retained collar cud

       Rotating collar cud (ES, July/August 2003)

       Unilateral split collar (theoretical only)

       Bilateral split collar


Die cracks



            Arcing rim-to-rim (“pre-cud”) (ES Jan/Feb 2006)

                 With lateral spread


       Bi-level die crack (ES July/August 2004)

            Protruding marginal die segments (CW 5/19/14)

       Radial, antipodal die cracks (with centralized subsidence) (ES Sept/Oct 2011; CW 6/20/2011)

       Die crazing (crazed die) (CW 2/24/14)

       Shattered die (ES Jan/Feb 2006, May/June 2007; CW 4/7/08)

            Two or more splits in die

            Numerous wide, intersecting, raised die cracks

            Numerous intersecting bi-level die cracks

            Various combinations of brittle fracture


Split die (ES Jan/Feb 2006; CW 6/2/03, 4/10/06, 4/17/06, 6/20/2011)


       Median (bisecting) split die

       Asymmetrical split die

       “False split” (bilateral, radial, antipodal die cracks) (ES Sept/Oct 2011; CW, 6/20/2011)




Part V. Planchet Errors


Alloy errors


       Improper alloy mix (CW 12/27/11)

            Poorly mixed alloy

            Incorrect proportions of metals

            In conjunction with rolled-thick errors (1941 cents, mainly) (CW 10/15/12)

       Gas bubbles (CW 11/19/12)

            Intact (“occluded”)


       Slag inclusion (ES May/June 2006)

       Intrinsic metallic inclusion (ES Sept/Oct 2006) (CW 12/27/11, 7/21/14)

       Lamination error

            Loss before strike

            Loss after strike

            Lamination crack

            Retained lamination

            Folded-over before strike (CW 10/22/12)

            Lamination within clad layer (CW 10/22/12)

       Split planchet

            Before strike (CW 8/2/10)

            After strike

            Struck with another planchet on top or beneath

            Split core (clad coins)

            Clamshell split (CW 1/28/13)

                  Clamshell folded over before strike (CW 10/22/12, 1/23/13)

       Copper-and-zinc composite “shells” (ES, May/June 2001)

                    Split-after-strike (N.B. these are probably all detached cap bottoms)

       Cracked planchet

       Broken planchet / coin (CW 3/14/11)

            Before strike

            After strike

       Brittle coin (cross-classified with annealing errors)

            Radial planchet splits (when struck out-of-collar)

       Crumbling planchet

       Ragged clip

       Ragged notch

       Ragged perforation (“blowhole”)

       Fissures -- ragged and smooth

       Other alloy errors


Corroded planchet (before strike)


       Copper-plated zinc cents


Rolling Mill Errors


       Rolled-thick planchet

       Rolled-thin planchet (CW 8/2/10)

       Tapered planchet (CW 12/20/10)

       Rolling indentation (ES Jan/Feb 2000; CW 2/7/11)

       Rolled-in scrap (ES May/June 2006; CW 2/7/11)

            Bristles from descaling brush (CW 3/10/03)

       Roller marks (CW 10/13/14)


Blanking and Cutting Errors


       Curved clip

            Crescent curved clip

            Bowtie clip (ES Nov/Dec 2005; CW 6/16/14)

                    Two large clips at opposite poles – ends rounded

                    Four clips – blanking die slices through previously punched strip

                    Struck chopped webbing

       Straight clip (CW 1/14/13)

            Smooth straight clip

            Irregular straight clip

            Sawtooth clip

            Incomplete straight clip (most likely just cuts from guides)

       Corner clip (“outside corner clips”) (CW 1/14/13)

       Assay clip (“inside corner clip”) (cross-classified with pre-strike damage) (CW 1/21/13)

       Ragged clip (also listed under alloy errors)

       Incomplete punch (incomplete clip) (ES May/June 2005; CW 3/24/14)

       Elliptical clip (ES May/June 2005; CW 4/5/10, 7/11/11))

       Multiple clips and combination clips (CW 1/27/14)

       Blanking burr (“rolling fold”) (ES Jan/Feb 2007; CW 1/31/11)

       Punched-in scrap (ES May/June 2006)


Upset Mill Errors


       Coin struck on blank (“Type I planchet”)

       Abnormally weak upset (ES July/August 2005)

       Abnormally strong upset (best seen on off-center strikes)

       “Groovy edge” (possibly from worn groove in upset mill)

       Variation in cross-sectional shape of rim/edge junction of planchet

       Struck coin sent back through upset mill

       Abnormal upset (ES Sept/Oct 2005; CW 2/27/12)

            Wide, flat edge

            Smoothly convex edge

            Abnormally wide proto-rim

       Squeezed-in debris (ES May/June 2006; CW 9/6/2010)

            Foil-like metal wraps around edge onto one or both faces

                  e.g. Copper foil on nickels (not from improper annealing)

            Metal wire wraps around edge onto one or both faces

            Pellet embedded in edge (CW 9/6/2010, 9/22/14)


Edge design errors (impressed into planchet before strike)

       (includes security edge errors)


       Edge design missing

       Edge design present on normally plain edge

       Wrong edge design

       Edge design too high or too low

       Interrupted edge design

       Tilted edge design


Mispunched center hole (foreign only)



       Double punched center hole

       Irregular center hole

       Unpunched center hole


Annealing Errors


       Improper annealing (due to excessive heat, prolonged exposure to intense heat, or excessive oxygen in annealing oven) (replaces “sintered plating” and “copper wash”) (ES July/Aug 2010; CW 11/30/09, 2/8/10)

            Black, brown, red, coppery discoloration (includes “black beauty” nickels)

            Layer of copper, often peeling

       Poorly annealed or non-annealed planchets (hard, brittle planchet) (CW 3/14/11)

            Broken planchet

            Broken coin

            Radial cracks in coin (usually struck out-of-collar)

       Brittle coin (cross-classified with alloy errors) (CW 3/14/11)

       Abnormally hard planchets (CW 12/17/12)

            1954-S nickels

            1983-P nickels (CW 4/11/11)

            “Superclash” 2000-P nickel (CW 3/22/10)

       On undersized or underweight planchets (CW 2/13/12)


Miscellaneous forms of mint discoloration


Plating Errors


       Incomplete plating

       Unplated cent

       Thin plating

       Thick plating (ES March/April 2009)

       Blistered plating

            Circular blisters

            Linear blisters

            Ruptured blisters

       Brassy plating

       Cracked, split, and peeling plating



Bonding/Bonding Mill Errors (ES Sept/Oct 2002)


       Missing clad layer


                  Before strike

                  After strike

                  Before rolling is completed (full weight) (ES Sept/Oct 2002, Nov/Dec 2006; CW 5/28/12)


                    Before strike

                    After strike

                    Before rolling is completed

            Thin cladding

                    With gaps

            Missing both clad layers (struck core)

                    Core thickness (ES, Sept/Oct 2003) (CW 3/18/13)

                    Full thickness

            Struck clad layer

                    Split off after strike

                    Split off before strike

                    Struck by itself

                    Struck on top of or beneath a normal planchet

            Clamshell separation (CW 1/28/13)

                    Clad layer folded over before strike

            Missing core


                    Full (Coreless or all-clad coins, 10c and above) (CW 12/19/11)


Irregular planchets


       Scraps / fragments (CW 12/21/09)

            Normal alloy/composition


            Feeder finger material


            Heavier than normal coin of same denomination

            Wider than normal coin of same denomination (along at least one axis)

       Ragged clip (cross-classified with alloy errors)

       Ragged notch (cross-classified with alloy errors)

       “Blowhole” (cross-classified with alloy errors)

       Fissure (cross-classified with alloy errors)

       Cracked planchets (cross-classified with alloy errors)


Pre-Strike Damage (CW 11/15/10, 11/15/10, 1/23/12, 1/30/12, 12/15/14, 4/6/15)


       Assay clip (cross-classified with blanking errors)

       Rim burr (CW 1/31/11)

       Accidentally and intentionally “resized” planchets (CW 9/15/10)

       “Cutmarks” (mostly found on off-metal errors 5c/1c, 5c/10c)

       Rockwell test mark in planchet (circular dimple) (ES July/Aug 2006)

       Planchet with adjustment marks (gold or silver planchets filed to reduce weight)

       Edge rolled, squeezed, and folded-over (or with thin apron produced)

       (CW 11/15/10; 1/23/12)

       Pre-plating damage (zinc cents) (CW 1/23/12)

       Post-plating damage (zinc cents) (CW 11/15/10)

       Scraped-in debris (CW 2/23/15)

       Repetitive pre-strike damage (CW 12/15/14)

       Other forms of pre-strike damage


            Crushed (CW 4/6/15)

            Scraped (CW 2/23/15)


            Crumpled (CW 8/15/11)


Inter-Strike Damage (CW 1/9/12, 8/20/12)


       Cancelled or defaced between strikes (CW 3/25/13)


Wrong planchet and off-metal errors


       Wrong planchet, correct composition




            Unidentified origin and purpose (orphan) (ES Sept/Oct 2006, Nov/Dec 2006, March/April 2011, May/June 2011; CW 5/10/10, 12/19/11)

       Foreign denomination struck on U.S. planchet

       Pure copper quarters and dimes (covered under bonding mill errors)

       Pure clad dime (covered under bonding mill errors)

       Wrong stock errors (CW 2/20/12)

            Correct composition

            Off-metal (e.g, 1987-P nickel struck on clad quarter stock) (CW 4/22/13, 9/23/13)

       Business strike on special off-metal planchet

            (e.g., 1974-D and 1977-D silver-clad Eisenhower dollar)

       Special strike on business planchet

            (e.g. 1973-S Eisenhower dollar on Cu-Ni clad planchet)

       Business strike on proof planchet (CW 11/14/11)

       Proof strike on business planchet

       Wrong date error (covered under mules and die manufacturing errors)       

       Double denomination errors

            Same year

            Different year

       Dual country (CW 3/21/11)

            Same year

            Different year (CW 3/21/11)

       Intentional overstrike (not an error)

       Transitional planchet error (“wrong series”) (ES Sept/Oct 2001)

            Transitional/wrong denomination error

                 (e.g. 1965 quarter struck on silver dime planchet)

       Struck on smaller planchet or coin

       Struck on same size planchet or coin

       Struck on re-sized planchet (dime design struck on cut-down cent planchet)

       Struck on larger planchet or coin

            1981 cent on nickel planchet, uniface reverse

            1981 cent design on struck SBA dollar (several known)

            1981 dime on cent cap

            Canadian “assisted errors” 1977 - 1981

       Struck on loose clad layer (covered under bonding mill errors)

       Weld seam planchets (controversial) (CW 9/24/12)

       Coin struck on washers, gears, and other hardware

       Coin struck on “aluminum” feeder finger

       Experimental issues

            Experimental wartime planchets (CW 12/7/09, 12/21/09)

            1999 and 2000 state quarters on experimental planchets (CW 11/26/01)

            1999 Susan B. Anthony dollars on experimental planchets (CW 8/5/02)

            1974 and 1974-D aluminum and bronze-clad steel cents (CW 1/13/03)



Part VI. Striking Errors


Unstruck blank (“Type I”)


Unstruck planchet (“Type II”)


Die alignment errors


       Rotated die error (CW 6/21/10, 7/9/12)

            Rotated die due to improper installation (fixed rotation)

            Rotated die due to improper die preparation (fixed rotation)

                  (e.g., grinding flats in wrong spot)

            Rotated die due to movement after installation (dynamic rotation)

            Semi-stable rotated die errors (various causes)

                        Characterized by a limited range of motion, a limited number of positions, or the presence of a single dominant position (CW 7/9/12)

       Pivoted die error (probably involves entire die assembly)

       Horizontal misalignment (CW 10/27/03)

            Hammer die (CW 2/1/10, 6/25/12)

            Anvil die (ES Sept/Oct 2004, March/April 2005; CW 9/27/10; CW 1/19/15)

                    With misaligned collar

                    With broken collar

            Dynamic misalignment (CW 6/25/12)

            Stable misalignment

       Vertical misalignment (tilted die error) (ES Jan/Feb 2003, Sept/Oct 2003) (CW 12/8/03, 12/20/10)

            Hammer die (CW 2/1/10, 6/17/13))

            Anvil die

            Dynamic misalignment

            Stable misalignment (CW 1/29/14)

            Associated with weak strike (10/8/12)

       Dual misalignments (both dies misaligned in different directions) (CW 11/28/11)

       Compound misalignments

            Horizontal and vertical

            Horizontal and rotated

            Rotated and vertical


Collar Alignment Errors


       Misaligned collar

            Associated with misaligned anvil die

            Associated with stiff collar error

            Associated with elliptical strike clip

       Rotating collar (detectable only when there’s a collar break and a multi-coin progression)


Collar deployment errors


       Partial collar

            Flange with bevel

            Flange without bevel

            Tilted partial collar

            Reversed partial collar (not an error)

       High deployment of collar with coin metal extruded beneath (controversial)




            Cupped broadstrike

            Forced broadstrike (CW 1/10/11)

            Partial collar broadstrike (shows incomplete, tilted partial collar)

       Stiff collar errors (ES, Nov/Dec 2000; CW 8/25/08)

            Strong collar scar

            Strong collar scar with cupping

            Planchet forced completely into fully deployed collar (“ram strike”) (ES Nov/Dec 2000, March/April 2001)

            Elliptical strike clip (ES March/Apr 2000; CW 4/5/10)

            Associated with weak strike (CW 2/11/13)


Weak Strikes (ES, Sept/Oct 2000; CW 5/3/04, 9/11/06, 6/18/07, 3/1/10, 5/23/11)


       Caused by insufficient die approximation

       Caused by abnormally low ram pressure

       Invisible strike (ES March/April 2003, Nov/Dec 2003, March/April 2004, Nov/Dec 2006, May/June 2010; CW 5/3/10, 9/20/10)

                        With indent

            With partial brockage

            With struck-through error

       Followed/preceded by strong strike

       Weak saddle strike

            One strike weak, one strong

            Both strikes weak (CW 12/12/11, 6/23/14)

       In combination with other striking errors


Abnormally strong strike


       Due to elevated ram pressure

            Finning (CW 8/23/04)

            Extremely large broadstrike (CW 7/26/10)

            Extreme stretch strikes with both sides die-struck

       Due to stacked coins or planchets

       Localized, due to die tilt


Stutter Strikes (ES Nov/Dec 2001, Sept/Oct 2007; CW 12/28/09, 7/25/11)


       Due to spasmodically collapsing or stiff collar (Type I)

       Due to planchet flexion (associated with indents and brockages) (Type II)

       Due to contact with bent planchet or coin (Type III)

            On face struck by anvil die (CW 8/26/13)


Concentric strike lines generated by a single strike (ES Jan/Feb 2012; CW 12/26/11)


Machine doubling (a.k.a. machine doubling, machine doubling damage, machine damage doubling, mechanical doubling, strike doubling, shift doubling, ejection doubling) (ES July/Aug 2006; CW 3/15/10)


            “Push doubling” (marginal shelving and sharp interior duplication)

            “Slide doubling” (smeared design)

            Intermediate forms

            Multiple machine doubling in one direction (two, three, and four serried ranks)

            Machine doubling in more than one direction (up to three directions)

            Machine doubling on both faces of same coin

            One-sided, rim-restricted design duplication (see separate category)

            Affecting incuse design elements (CW 2/6/06, 1/16/12)

            Located on top of die break

            Located on top of die attrition error (CW 4/14/14)


One-sided, rim-restricted design duplication (form of machine doubling) (CW 10/6/03, 2/22/10, 5/24/10, 12/6/10, 5/13/13, 12/30/13)


       2004 cent (ES March/April 2007; CW 2/22/10)

       1994 cents (CW 5/24/2010, 8/22/2011)

       1981-P quarter and 1979-D dime (CW 12/30/13)

       Presidential dollars (ES, Sept/Oct 2007) (CW 2/22/10, 12/6/10)

       Foreign coins (CW 2/22/10)

       On face struck by anvil die (CW 10/21/13)


Design ablation error (design scraped off by die movement) (ES March/April 2008, Jan/Feb 2011; CW 9/13/10)


       On first strike

       On second strike


One-sided multi-strikes (ES March/April 2000, Jan/Feb 2002, July/August 2003)


       Hammer die rotated (CW 11/29/10)



       Hammer die misaligned



       Anvil die misaligned (CW 9/9/13)

       Anvil die rotated (at least one known example, a proof Kennedy half dollar)

       False one-sided double strikes (CW 11/29/10)


Flat Field Doubling (Imperfectly Aligned Proof Strikes) (CW 4/29/13)


Off-center strikes


       Cupped off-center strike

            With collar scar

            Without collar scar

       Uniface strike

       Stretch strike


            Die struck on both faces (covered under high pressure strikes)

       With unexplained, flat dent at opposite pole

            (not a “sideneck strike”)



Chain strike (CW 4/12/10)


       Normal chain strikes with straight edge

       External chain strikes(ES Jan/Feb 2003)

       Concave, convex, sinuous, and irregular chain strikes (ES Jan/Feb 2001, July/August 2002; CW 4/12/10)


Wraparound strike (theoretical, so far)


       Edge of off-center coin wraps around obstruction on die face


Saddle Strike (CW 6/27/11)


       Hump present

       Hump absent

       Die position


            Head-to-base (early to mid- '70s, mainly)

            Other orientations

       Gap between adjacent dies



       Sideneck strikes (“one-die saddles”) (Expanding planchet collides with side of die neck) (CW 5/30/11)

       With inverted die installation


Broadstrike (covered under collar deployment errors)


Split Plating Doubling


Foldover Strike (ES July/August 2007; CW 10/10/05, 8/15/11, 1/30/12, 9/15/14)




       With edge strike persisting

       On struck cents (normal and error)

       Double foldover strikes (“Z-fold”)

       Axial fold

       Paraxial fold

       Inward fold

       Outward fold


Edge Strike (CW 7/18/11)




       With off-center strike or broadstrike produced by continuation of downstroke


Extrusion strike (an effect, not an independent error) (ES March/April 2004; CW 10/24/11)


       With indent or partial brockage

       With struck-through error



Multiple strikes (CW 3/30/15)





       Numerous closely-spaced strikes (ES Nov/Dec   2004)

       Involving more than one die pair

       Delayed second strike (ES July/August 2007; CW 1/9/12)






       Full (CW 7/30/12)



       “Internal” indents (CW 11/1/10)

            On obverse

            On reverse

       Multiple indents

       Irregular indent

            Produced by error coins

            Produced by clipped planchet

       Indent by smaller planchet (CW 5/19/08)








            Rotated brockage (relative to die-struck design on opposite face)



            Aligned partial brockage (ES, May/June 2005; CW 1/17/11)

                    From partial die cap

                    From elliptical clip coin

                    From elliptical strike clip

            Internal partial brockage (CW 11/1/10)


       From another, smaller denomination (ES May/June 2005)

       From another error coin

       Flipover brockage

            On obverse

            On reverse

       First-strike brockage

            “Mirror” brockage (unexpanded, undistorted) (CW 6/13/11, 3/17/14)

            Distorted first-strike brockages

       Mid-stage and late-stage brockages

       By struck fragment (CW 6/11/12)

            Aligned with opposite, die-struck design

            Not aligned with opposite design

       From struck die fill (very rare)

       Multiple brockages CW 9/26/11)

            From multiple strikes

            From clashed cap

            From multi-struck coin

            From more than one coin in striking chamber

            From coin trapped between die cap and planchet

       Clashed cap strike (CW 8/30/10, 11/21/11, 1/13/14)

            From a late-stage die cap that clashed with the opposite die

            From a uniface die cap that clashed with the opposite die

            From an early-stage die cap that clashed with the opposite die

            From a cap that was striking counterbrockages that clashed with the opposite die

            From a flipover die cap that clashed with the opposite die (CW 1/13/14)




       Full (CW 10/11/10)

       Partial (CW 11/8/10)


       Counterbrockage of obverse on obverse

       Counterbrockage of reverse on reverse

       Flipover counterbrockage

       Early, middle, and late-stage counterbrockages

       From another error coin

       Brockage-counterbrockage combination (8 types) (ES, Nov/Dec 2009) (CW 11/12/12)

       Multiple counterbrockages (ES March/April 2010)

       On second strike


Die caps


       Obverse die cap (obverse die functioning as hammer die)            

            Raised reverse design

            Brockage on reverse face

            Uniface die cap

            Complex die caps

       Reverse die cap (reverse die functioning as anvil die)



            Cupped toward anvil die, hammer die, both dies at opposite poles, or expanded in the horizontal plane

       Partial (off-center) die cap (hammer or anvil) (CW 1/17/11)

            With cupping

            Without cupping

       Detached cap bottom (ES March/April 2001, May/June 2001)


Capped die strikes (generic -- without identifiable images)


       Struck by uniface die cap

       Struck through late-stage die cap

       Struck through cap-like obstruction

       Struck through split or torn cap

       Both faces struck through die cap or cap-like obstruction (CW 11/11/13)


Struck by impaled die cap (CW 6/10/13)


Capped die doubling (doubling associated with capped die strikes) (ES Sept/Oct 2005; CW 6/18/12)


       Shifted/rotated cap strikes (ES May/June 2000, March/April 2012; CW 11/21/11)

            Normally-oriented incuse design elements (CW 11/3/08, 6/28/10, 6/11/12)

                    Multiple sets due to several preceding shift-and strike events

            Unexplained, close raised doubling

                  Expansion ripples

                  Other forms of close raised doubling

       Incuse doubling surrounding raised elements


“Struck-through” errors


       Struck through fragment

       Struck through clipped planchet (ES Sept/Oct2002; CW 8/25/14)

       Struck through thin struck fragment (CW 6/11/12)

            Face-up (normally-oriented incuse design elements)

            Face-down (mirror-image design elements)

            Trapped between planchet and opposite die (mirror-image design elements)

       Struck through detached lamination flake (CW 2/7/05, 6/11/12)

       Struck through clad layer

            Clad layer unstruck

            Clad layer previously struck

       Struck through loose (sheared-off) reeding

       Struck through split planchet



       Struck through hardware (bolts, screws, washers, etc) (CW 3/7/11)

       Struck through feeder finger (ES Nov/Dec 2005; CW 3/7/11)

       Struck-through unidentified machine part (CW 6/24/13)

       1986 Silver Eagles struck through emery disc (CW 12/16/02)

       Struck through die fill

            “Grease strike” (many kinds of die fill and resulting textures)

                    Struck through smooth, viscous material (grease,oil)

                    Silvery, flaky die fill (some state quarters)

                    Black, crusty die fill

                    Doubling associated with (ES March/April 2006, July/August 2006, Nov/Dec 2008)

                    Ghost images from grease accumulations (“greasy ghosts”)

                    Grease mold doubling (CW 8/19/13, 10/20/14)

       Struck through miscellaneous foreign matter

            Metal dust, shavings


            Cloth (CW 5/14/12)


       Field-restricted struck-through errors (CW 11/18/13)

       Split or torn in two by struck-thru object (ES Nov/Dec 2007; CW 3/7/11)

       Dropped filling (ES May/June 2003; CW 8/16/10, 6/11/12; 10/29/12))

            Isolated elements (“dropped letter”, “dropped number”) (CW 2/7/05)

            Conjoined dropped fillings (CW 8/16/10)

            Large dropped filling incorporating numerous design elements (CW 4/19/10, 8/16/10)

            Retained dropped filling

       Retained struck-through errors (struck-in errors)

            Embedded dropped filling (see above)

            Embedded die fill (shapeless)

            Scrap metal

            “Staple” (bristles from wire brush)

            Plastic (associated with bullion coins)

            Metal foil

                   (Cu-Ni?; associated with dimes and nickels)

                  Copper foil (ES Nov/Dec        2007)

            Rubbery material (from die cover?)


       Filled dies

            Single design elements

            Multiple design elements

       Filled collar /obstructed collar (ES Jan/Feb 2006; CW 9/22/14)

            With flange

       Surface film effects (ES May/June 2002; CW 9/1/08)

            Surface film doubling

            Surface film afterimage

            Surface film transfer

            Surface film transfer with clash marks


Uniface strike (cross-classified with Indents) (CW 7/30/12)







Sandwich strike (coin struck between two coins or planchets) (CW 5/16/11)




       Between two struck coins

       Between two planchets

       Between a coin and a planchet

       Between obverse and reverse die cap


Nested coins


Mated pairs


Bonded coins


Pile-ups (clusters)


Ram strike (see Stiff Collar Errors) (ES Nov/Dec 2000)


       Normal die installation (pre-1997)

       Inverted die installation (post-1997)

       Association with misaligned dies

       Association with misaligned collar


Strike clips (ES July/Aug 1999, May/June 2001)


       Conventional strike clips

       Elliptical strike clips (several kinds) (CW 4/5/10)

       Saddle strike/strike clips

       “Pinch clips”





Detached reeding


       From forced broadstrikes

       From stiff collar

       Torn-off fin




Coin shrapnel (“breakaway fragments”)


       Angular pieces

       Crescentic pieces

       Roughly circular pieces

       Semilunar pieces

       Other shapes


Intra-Strike Damage (Damage coincident with strike) (CW 5/30/2011)


       Flat contact facet opposite off-center strike

       Dual contact facets in multi-struck coins


Cupping (CW 12/7/09)


       With and without collar scar

       In a single strike

       Associated with multiple strikes

       With die caps

       Cupping toward hammer die

       Cupping toward anvil die

       Expansion in horizontal plane


Impact-Induced Warping (CW 3/16/15)


Bi-metallic errors (foreign only) (ES Nov/Dec 2005)


       Misaligned core (ES May/June 2007)

       Misaligned center hole (ES Sept/Oct 2007)

            Well-seated core

            With misaligned core

       Double-punched center hole

       Unpunched center hole

            Solid disc of ring metal

            Solid disc of ring metal with embedded core

            Solid disc of ring metal with core indent

       Ring with incomplete punch (ES Sep/Oct 2007)

       Core with incomplete punch

       Struck outer ring (ES Jan/Feb 2007)

       Struck core (ES Nov/Dec 2006)

            From another denomination

            From another country (ES Sep/Oct 2009, Nov/Dec 2011)

            Struck by solid-denomination dies

       Wrong core inserted (ES Sep/Oct 2013)

       Wrong ring (ES March/April 2007)

       Ring accidentally punched from solid planchet

       Ring accidentally punched from solid coin (ES Nov/Dec 2008)

       Struck ring from another country (restruck)

       Struck core from another country (restruck)

       Unstruck core inserted into struck ring and then restruck

       Abnormally small core (controversial)

       Abnormally wide center hole (controversial)

       Abnormally thin core

       Abnormally thick core

       Abnormally thin ring

       Abnormally thick ring

       Incomplete trilaminar core

            Missing one layer (ES Mar/Apr 2010)

            Missing two layers

       Core punched out of ring strip

       Ring punched out of core strip

       Bi-metallic planchet struck by solid-denomination dies

       Solid-denomination planchet struck by bi-metallic dies (ES Mar/Apr 2014)

       Bi-metallic planchet struck by wrong bi-metallic design


Malrotation Errors (multi-sided coins only) (CW 3/23/15)


Proof edge lettering errors (generated during strike by segmental collar)

       Weak edge design due to segmented collar not closing fully (wide seams)

       Segments arranged in incorrect sequence (see Die Installation Errors) (CW 4/7/08)





Part VII. Post-Strike Mint Modifications


Edge lettering applied after strike (incuse) (Business strike Presidential dollars, Native American dollars, and final Sacagawea dollars)


       Absent lettering (CW 4/26/10)

            Due to bypassing the lettering device

            Due to excessive spacing between steel wheel and lettering die

       Vertically misaligned letters (cut off at top)

       Vertically misaligned letters (cut off at bottom)

       Wrong spacing between incuse design elements

       Obliquely-oriented lettering

       Overlapping letters

       Two sets of letters

       Skipped letters

       Letters on wrong planchet

       Chipped letter

       Lightly impressed letters (CW 4/26/10)

       Letters impressed too deeply and coin squeezed too hard

       Incomplete letters

       Smeared letters

       Edge letter font subtypes (CW 10/18/10)

       Wrong date on edge (doesn’t match any President of that year) (CW 2/22/10, 3/1/10)

            2009 Zachary Taylor dollar with 2010-D edge inscription (CW 2/22/10, 3/1/10)

       2007-D Sacagawea dollar with Presidential edge lettering (CW 7/9/12)

       Edge lettering on unstruck planchet (CW 3/26/07, 3/17/08)


Note: Edge lettering and other edge design elements may be impressed during upsetting, during the strike, by a special machine before the strike, or by a lettering device after the strike. Similar-looking defects can occur in each of these processes.  Any edge design that forms a closed interlock between the edge of the coin and the collar cannot be produced during the strike since that will prevent ejection of the coin after the strike.


Post-strike chemical treatment


       Anti-tarnishing Experimental Rinse on Sacagawea dollars

Matte or frosted finish applied after strike


       Finish omitted on one or both faces (CW 8/1/11, 8/29/11)




Part VIII. Post-strike die contact


Ejection impact doubling (post-strike design transfer from die) (ES Jan/Feb 2004) (CW 8/1/05, 8/29/05, 2/25/13))



Part IX. Post-strike mint damage


Pseudobrockage (false brockage) (ES Nov/Dec 1999) (CW 8/23/10)


Fused coins


Rolled and squeezed


Accidentally resized


Other (folded, crushed, scraped, bent, etc.)



Part X. Wastebasket/Composite Categories


Ghost images (CW 8/1/11)


       Progressive, indirect design transfer

       Worn clash marks

       Thin planchet (CW 8/2/10)

        Split planchet

            Split-before-strike (CW 8/2/10)

            Split after-strike

       Coin thinned by strike(s)

       Weak strike (CW 4/11/2011)

       High pressure strike

       “Greasy ghost” (CW 7/5/10)

       Surface film afterimage (CW 5/2/11)

       Surface film transfer (CW 5/2/11)

       Split plating afterimage (CW 5/2/11)

       Coarsened crystallite afterimage (CW 5/2/11)

       Other causes




       Die Deterioration Doubling



       Machine Doubling

       “Abrasion doubling” (extremely doubtful) (CW 7/15/13)

       Split plating doubling (split-line doubling) (CW 3/26/12)

       Surface film doubling

       Grease Mold Doubling (CW 8/19/13)

       Longacre doubling

       Offset laser-etched frosting on proof dies (CW 2/21/2011)

       Plating disturbance doubling (CW 3/28/2011)

       Flat-field doubing (imperfectly aligned proof strikes (CW 4/29/13)

        Other forms of doubling


Embedded matter (CW 12/14/09)




            Intrinsic metallic inclusion


        Punched-in (by blanking die)

        Squeezed-in (by upsetting mill) (CW 9/6/10)

        Scraped-in (CW2/23/15)





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