Mint Error vs Post-Mint Damage: The Tests That Separate Them

The four tests

Raised or incuse. A die can only push metal up. Anything cut into the surface — a line, a hole, a gouge — was made by a tool after striking. The single exception is the faint incuse ghost of a die clash, which matches the opposite design exactly.

Bright or toned. Damage exposes fresh metal. On a circulated coin, a feature with bright, sharp edges is recent. A mint feature on a circulated coin is as worn and toned as the surfaces around it.

Displaced or absent. An impact pushes metal up in a ridge around the point of contact. Mint errors that remove metal — clips, laminations — leave no ridge, because the metal was never there or came away cleanly.

Mechanical cause. Name the mint process. If no process produces the feature, it is damage. The master guide lists every process.

Lamination vs corrosion

A lamination is a layer of metal separating along an internal flaw. The separation plane is clean, the edge of the missing area is stepped and layered, and the surface underneath is smooth metal that was never exposed to air. Corrosion is chemistry eating the surface. The affected area is pitted and rough, the edge is irregular and eaten rather than stepped, and the surrounding surfaces usually show the same chemistry in milder form. A lamination sits on an otherwise normal coin; corrosion is the worst spot on a coin that is corroded everywhere.

Clipped planchet vs cut coin

A clip happened before the coin was struck, so the strike and the upsetting mill both reacted to it. The rim opposite the clip is weak — the Blakesley effect — because the mill had nothing to push against. The design fades toward the clip rather than stopping at a line. The clip's edge is unstruck planchet, dull and unreeded. A cut coin was a complete coin that lost a section afterward. The opposite rim is full. The design stops sharply at the cut. The cut edge is bright and shows tool marks. Photographing the Blakesley effect is the confirmation.

Struck-through vs worn or damaged area

A struck-through is a missing or weak area where an object sat between die and planchet. The area has the texture of the object — cloth weave, a wire's shape, a grease-filled smoothness — and the surrounding strike is normal. There is no displaced metal, because nothing hit the coin. A worn area shows abrasion on the high points with the low points intact. A damaged area shows a tool's signature and a ridge of displaced metal. The tell is texture: struck-throughs carry an impression, damage carries a scrape.

Die crack vs scratch

A die crack is a raised line on the coin because it was an incuse crack in the die. It has a rounded profile, it is toned like the rest of the coin, and it often runs through design elements without disturbing them. A scratch is incuse, has bright sharp walls on a circulated coin, and cuts through design elements. Run a fingernail across it: raised catches, incuse does not. Cud vs die crack vs die chip covers the die-crack family.

Brockage vs vise job

A brockage is a coin struck against another coin that stuck to the die. The incuse image is a full, expanded, mirror-image copy of the opposite design, struck with press pressure into a fresh planchet, so the whole coin is uniformly fresh. A vise job is a worn coin squeezed against another coin. The impression is partial, crude, and not expanded; the coin shows flattening and displaced metal around it; and the original design under the impression is worn while the impression is sharp, which is impossible if both happened at the mint.

Rim cud vs rim damage

A cud is a raised, featureless area at the rim where a piece of the die broke away, and the design on the opposite side is weak in the corresponding area because the metal flowed into the void. Rim damage is a dent or a ding: incuse or flattened, with displaced metal beside it, and with a normal opposite side. A cud is a feature the die made; a ding is a feature something else made afterward.

Wrong metal vs plating and toning

This pair is settled by weight and by nothing else. A wrong-planchet coin weighs what the other coin's planchet weighs. A plated, toned, or chemically altered coin weighs what it always did. Color is irrelevant. Color does not prove wrong metal and calibrate your scale are the two pages that resolve this every time.

The habit

Apply the four tests in order, before you decide what the coin is. Raised or incuse. Bright or toned. Displaced or absent. Named cause or none. A coin that fails any test is damage, and the not-an-error hub will tell you which kind. A coin that passes all four is a candidate, and the error types hub will tell you what to confirm next. Most coins fail the first test. That is not a disappointment; it is the method working.