The Coin Tray · 58 articles
The Coin Tray
All 58 articles from ErrorCoins.co, newest first. Search, filter by topic, or sort to find the one you need.
Two-Headed Coins: Magician's Novelty or Real Mint Error?
Found a two-headed or two-tailed coin? Learn how novelty coins are made, the edge and weight checks that expose them, and what a genuine mule error really is.
Two-Headed Coins: Magician's Novelty or Real Mint Error?
Found a two-headed or two-tailed coin? Learn how novelty coins are made, the edge and weight checks that expose them, and what a genuine mule error really is.
Struck-Through Errors: Cloth, Wire, Thread, and Debris Explained
How struck-through cloth, wire, thread, staple, and fragment errors form, what each leaves on a coin, and how to tell them from post-mint pressing and damage.
Repunched Dates and Overdates: How to Identify and Attribute Them
How repunched dates (RPDs) and overdates form, how to read secondary digits under magnification, and how to rule out machine doubling, damage, and alterations.
Indent Errors: How to Identify a Coin Struck With a Planchet on Top
How indent errors form when a blank planchet lands on another during striking, how to read the smooth curved depression, and how indents differ from brockages.
How to Store Odd-Shaped Error Coins Without Damaging Them
General coin storage advice assumes a flat, round coin of standard size. Error coins break that assumption constantly. Broadstrikes are wider than the holder, die caps are cup-shaped…
Gifts for Error Coin Hunters: Ideas by Budget, From Stocking Stuffers Up
Holiday gift ideas for error coin and variety hunters, sorted by budget: loupes, scales, references, roll boxes, microscopes, and how to buy a certified error.
Die Cap Errors: How a Stuck Coin Becomes Part of the Die
How die caps form when a struck coin sticks to a die, what deep and shallow caps look like, how capped die strikes differ, and how to spot fakes and damage.
Blank Planchets: Type 1 vs Type 2, and How to Tell a Real One
Learn how Type 1 blanks and Type 2 planchets differ, how to check rim, edge, weight and diameter, and how to rule out sanded or erased coins posing as blanks.
A $50,000 Asking Price Is Not a Coin Value
Unsold marketplace prices are not comparables. Exact completed sales and matched attribution matter.
Repunched Mintmarks (RPM): How to Identify and Attribute Them
How to spot a repunched or over mintmark, tell it apart from machine doubling and damage, describe its direction, and match it to a published attribution.
Missing Clad Layer Errors vs Acid-Treated Coins: How to Tell
A copper-colored quarter or dime can be a missing clad layer error or a chemically altered coin. Learn the edge, weight and surface tests that tell them apart.
Mint Error vs Die Variety: Why the Difference Changes Everything
A mint error happens to one coin; a die variety repeats on every coin from one die. Learn why that difference changes how you identify, attribute and research.
Loupe vs Stereo Microscope: Choosing Magnification for Error Coins
Which magnifier do you need to spot doubled dies, die cracks and clips? Compare loupes, stereo microscopes and USB scopes, and the light that shows relief.
Lamination Errors vs Plating Bubbles: Is That Peeling Metal an Error?
Peeling metal can be a lamination error or simply corroded plating on a zinc cent. Learn what causes each, the tests that separate them, and when it matters.
How to Get a Coin Variety or Error Attributed, Step by Step
A step-by-step path from "I think it's a doubled die" to a documented attribution: matching diagnostics, photos, specialist help and grading submissions.
Why Most “Error Coin” eBay Listings Are Really Damage
Many eBay listings labeled error coin show post-mint damage, wear or normal coins. Learn the red flags in titles and photos and how to find real errors.
Double-Struck Coins: How to Identify a Multiple-Strike Error
How to identify double-struck and multiple-strike error coins, tell them apart from doubled dies and machine doubling, and document the strike order.
Die Clash Marks: How to Spot the Ghost of the Other Side
Die clashes leave faint outlines of the opposite design on a coin. Learn how clashes form, how to spot and orient them, and what they get confused with.
Coin Roll Hunting for Errors and Varieties: A Practical Routine
A practical routine for searching bank rolls for mint errors and die varieties: what to check first, a sorting workflow, tools, record keeping and common traps.
Wrong Planchet Errors: Weight and Composition Evidence
Wrong Planchet Errors: Weight and Composition Evidence. Striking on the wrong blank must be evaluated against measurements and metallurgy. Check the crucial e
Struck-Through Grease Errors: Weak Details or Wear?
Struck-Through Grease Errors: Weak Details or Wear?. Missing details from a strike-through require differentiation from abrasion. Check the crucial evidence,
Rotated Die Errors: Photographing Alignment Correctly
Rotated Die Errors: Photographing Alignment Correctly. Rotation claims must establish the relationship of obverse and reverse. Check the crucial evidence, ris
Off-Center Lincoln Cents: Distinguishing Strike Error From Damage
Off-Center Lincoln Cents: Distinguishing Strike Error From Damage. A true off-center strike often preserves a visible unstruck planchet portion. Check the cru
Weighing Foldovers, Caps and Bonded Errors
How to support irregular pieces without losing calibration accuracy.
Raw Error Coin Return Checklist
What to test immediately while a marketplace return window remains open.
Documenting Mated Error Pairs
A record system for preserving fit, orientation, strike order and provenance.
How to Estimate Off-Center Percentage
A geometry-based method for describing off-center strikes consistently.
Sorting a Family Box Labeled Errors
Preserve old notes while separating certified errors, varieties, damage and ordinary coins.
Create an Edge-Lettering Sequence Sheet
A printable photography and transcription workflow for lettered-edge coins.
Building a Die-State Progression
How repeated examples can document the growth of chips, cracks, cuds and clashes.
Coin Microscope Settings That Do Not Invent Detail
Lighting, focus and sharpening practices that reduce false doubling.
Photographing the Blakesley Effect
How to show opposite-rim weakness on genuine clipped planchets.
Build an Error-Coin Auction Archive
Columns for exact configuration, certification, date, price and images.
Write Observations Before the Attribution
Describe raised, incuse, missing, displaced, weak, doubled, or altered metal before choosing a category.
Why “No Mint Mark” Usually Is Not an Error
Many Philadelphia circulation coins were intentionally issued without a mintmark. The date, denomination, proof status, and normal mint policy matter more than absence alone.
Why Color Does Not Prove a Wrong-Metal Error
Toning, plating, corrosion, chemicals, lighting, and coatings change color. Weight, edge, dimensions, and composition evidence are required.
Tiny Die Chips and Giant Price Claims
A named blob or viral nickname does not automatically create rarity or strong demand.
The One-Photo Error Coin Problem
A single close-up hides the host coin, edge, opposite face, scale, and metal-flow evidence needed for identification.
Preserve the Old Envelope With the Coin
Old labels, dealer envelopes, receipts, and family notes can preserve provenance even when an old attribution proves wrong.
Machine Doubling Versus a Doubled Die
Flat shelf-like strike displacement differs from hub doubling created on the die.
The Full Edge Is Half the Identification
The edge can expose missing clad, seams, reeding, collar effects, jewelry damage, repairs, and edge lettering.
Calibrate the Scale Before Claiming a Transitional Error
A few tenths of a gram can separate compositions, but scale drift, dirt, holders, and tolerance can mislead.
Error Coin Value Research: Matching the Same Error Severity
Error Coin Value Research: Matching the Same Error Severity. A sold comp must match coin type, severity, grade and certification status. Check the crucial evi
Doubled Die Versus Machine Doubling: What to Compare
Doubled Die Versus Machine Doubling: What to Compare. Hub doubling and mechanical shelf-like doubling have different diagnostic characteristics. Check the cru
Die Cracks Versus Post-Mint Scratches on Coins
Die Cracks Versus Post-Mint Scratches on Coins. Raised metal along a die crack differs from incuse scratches. Check the crucial evidence, risks and realistic
Clipped Planchets: Blakesley Effect and Confusing Damage
Clipped Planchets: Blakesley Effect and Confusing Damage. A missing segment can result from production or post-mint alteration. Check the crucial evidence, ri
Brockage Errors: Mirror Image Identification
Brockage Errors: Mirror Image Identification. An incuse reversed image can form when a struck coin obstructs the die. Check the crucial evidence, risks and re
Broadstrike Coins: Why the Missing Collar Matters
Broadstrike Coins: Why the Missing Collar Matters. A broadstrike expands beyond normal diameter when not constrained by collar. Check the crucial evidence, ri
Off-Center vs Broadstrike vs Misaligned Die: Three Striking Errors Compared
The three striking errors that get confused with each other — off-center strikes, broadstrikes, and misaligned die strikes — compared by cause, appearance, edge, both sides, and value, with…
Not an Error: Post-Mint Damage, Machine Doubling, Die Wear, and Altered Coins
The reference hub for everything that looks like a mint error and is not — post-mint damage, machine doubling, die deterioration, missing mint marks, plating and toning, vise jobs, and…
Mint Error vs Post-Mint Damage: The Tests That Separate Them
How to tell a genuine mint error from post-mint damage — the raised-versus-incuse test, the bright-edge test, the displaced-metal test, and the mechanical-cause test — applied to the pairs…
Mint Error Types Explained: Die, Planchet, and Striking Errors
A reference hub for every major mint error type organized by mechanical cause — die errors, planchet errors, and striking errors — with the identifying features and confirmation test for…
Genuine vs Altered 1943 Copper Cent: Every Test, in Order
How to test a 1943 cent that looks like copper — the magnet test, the weight test, the date-shape test, and what each result means — plus why almost every copper-colored 1943 cent is a…
Error Coins: The Complete Identification Guide
The master guide to identifying mint error coins — the three error families (die, planchet, striking), the fourth category of things that are not errors, a triage method for any suspect…
Error Coin Grading and Certification: PCGS, NGC, ANACS, and CONECA
How mint errors are certified and graded — which services handle errors, what the label says, how attribution differs from certification, when certification is worth it, how to submit an…
Doubled Die Coins: Identification and Attribution
How doubled dies are made, the classes of hub doubling, the diagnostic features that separate a true doubled die from machine doubling and die deterioration, how to attribute a doubled die…
Die Deterioration Doubling vs True Doubled Die: How to Tell Them Apart
Die deterioration doubling is a die state; a doubled die is a die error. They look alike to a new collector and nothing alike to an experienced one. The diagnostic differences, where each…
Cud vs Die Crack vs Die Chip: The Die-Break Family Compared
Cuds, die cracks, and die chips are stages and forms of the same thing — a failing die. How each forms, how each looks on the coin, how to tell them from damage, and why size and drama…