Glossary
Every term that ever appears on an IGA certificate, defined with care. Browse by category, jump by letter, or search for the word you need.
145 terms across 6 categoriesPress / to focus, Esc to clear
Codes and qualifiers that appear before or beside the numeric grade.
An intentional mint-applied finish that gives the coin or medal an aged, oxidized appearance — used on modern medals and special issues.
A proof-coin designation indicating a moderate frosted contrast between the devices and the mirrored fields on both sides.
The highest contrast proof designation: heavily frosted devices set against deep mirrored fields on both sides.
A higher tier of prooflike with deeper, sharper reflectivity across the fields, typically commanding a market premium.
A label modifier for coins received for grading within a defined early window after their official release date.
A modern surface treatment combining selectively frosted and polished elements, distinct from standard mint state.
A reverse proof issue with additional contrasting finish techniques applied to selected design areas.
A label modifier for coins certified as released on the official first day of issue, often tied to event documentation.
A generic industry concept for coins certified during the initial release period of a new coin program.
A coin or medal struck with elevated relief, where the design rises noticeably above the field.
A non-reflective, evenly textured finish, used historically and on certain modern special issues.
A proof issue with a uniformly matte (non-reflective) finish rather than mirrored fields.
A proof issue produced with intentional modifications to the standard proof process, recognized for its distinct finish.
A modifier appended to numeric grades to indicate a coin solidly at the high end of its grade.
Indicates a coin produced by the proof minting process; describes the strike type, not the numeric grade.
A surface designation given when a coin's fields are clearly reflective, approaching proof-like appearance though not a true proof.
A proof-format coin where the mirrored and frosted areas are reversed: frosted fields and mirrored devices.
Coins produced as part of a special-strike program, with finish characteristics between business strike and proof.
A prefix used for specially struck pieces that fall between business strike and full proof issues.
A modifier appended to numeric grades to recognize exceptional eye appeal for the grade.
A coin or medal with extreme intentional relief — the highest tier of designed relief, typically reserved for modern art coins.
Errors that originate inside the minting process — planchet, die, and striking.
A metal disc that left the mint production line before being struck by the dies. No design appears on either side.
The collar failed during striking, so the coin spread outward and is wider and thinner than normal.
A mirror image of the design caused when an already-struck coin stuck to a die and acted as the die for the next strike.
A defect originating in the hub used to make the die, transferring to every die produced from it.
Two or more coins struck linked together along their edges in a single event.
A portion of the planchet is missing because of misalignment in the blanking process at the mint.
A specific die break at the rim that produces a raised, blob-like area at the edge of the coin.
A more advanced die failure where a portion of the die has broken away, producing a raised blob on the coin.
A coin that adhered to a die for many strikes, deforming into a thimble or cap shape.
Marks on the coin caused by the two dies striking each other without a planchet between them.
A raised line on the coin caused by a crack in the die that filled with metal during striking.
The same planchet was struck twice by the dies, creating two overlapping impressions of the design.
A doubling of design elements caused during die manufacturing, present on every coin struck from that die.
A planchet that was struck while standing on its edge rather than lying flat between the dies.
Design weakness caused by grease, dirt, or debris filling the recesses of a die.
The planchet folded or bent during the striking process, producing a distorted, partially folded coin.
A planchet produced with an incorrect or unevenly mixed alloy, often visible as streaks or unusual color.
The planchet itself was not fully formed before striking, producing an irregular outline from the start.
An impression left in one coin by another coin or blank that overlapped it during striking.
A surface flake or peel caused by impurities or gas pockets trapped between layers of the metal.
One die was offset relative to the other during striking, producing uneven design placement.
A planchet struck three or more times, producing multiple overlapping impressions.
The planchet was not properly centered when struck, leaving part of the design missing and part of the planchet blank.
A coin where the collar was partially engaged at striking, leaving a stepped or "railroad rim" edge.
A minor pre-strike defect on the planchet that survives the strike and remains visible on the finished coin.
A rim die break where the broken die piece is still partially in place, producing a softer raised area.
A struck-through error where the foreign object remains embedded in the coin after striking.
Two coins fused together because they were struck in contact with each other.
The coin was struck with a foreign object between the planchet and the die, leaving its impression on the surface.
A specific struck-through error caused by grease filling part of the die at the moment of strike.
Two planchets overlapped during striking, leaving one side fully designed and the other blank or near-blank.
A coin struck on a planchet intended for a different denomination, alloy, or country.
Patterns, essais, trials, specimens, and other non-circulation material.
A piece whose value lies primarily in presenting a proposed artistic design that may not have been adopted in final production.
A test impression taken from a die to evaluate its design, depth, or condition during the engraving process.
A proposal piece showing a design idea for a proposed coin, medal, or issue — the wording is common in world coinage.
A pattern piece used to test a broader change in metal, weight, thickness, or edge — the experimental aspect is more pronounced than in a standard pattern.
An unofficial piece that imitates the look of a pattern or trial but was not produced under any official authority.
A test impression taken from a hub or master tool used to produce dies — typically a one-sided proof of the design.
A trial coin produced by or under the authority of a mint to test a proposed design, alloy, size, or edge before official adoption — intentional, not an error.
A piece made later, outside the issuing authority, to mimic a known pattern or trial piece. Not genuine.
A later issue struck from original or recreated dies, often well after the original mintage date — not the original issue.
A coin produced for a special mint set or similar program, with finish characteristics between business strike and proof.
A coin produced as part of an intentional special-strike program, distinct from both regular circulation strikes and full proof issues.
A piece struck with above-normal care, typically with sharper detail and better surface, but not a full proof.
A soft test strike, often in a soft metal or lead, used as a quick check of die appearance during setup or repair.
Issues that result in a Details holder — numeric grade is suppressed but the coin is encapsulated.
A coin whose color has been altered by artificial means rather than by natural toning.
Toning patterns or colors produced by chemical or heat treatment rather than natural environmental exposure.
A coin that has been physically bent out of its original flat shape.
A coin treated with a wire or stiff brush, leaving fine parallel marks across the surface.
A coin polished aggressively to mirror-like brightness, masking original surface qualities.
A coin where chopmarks have been smoothed, filled, or otherwise hidden after the fact.
A coin bearing one or more merchant marks struck into the surface to verify metal content during trade, historically common in Asian markets.
A coin that has been cleaned, leaving evidence on the surface that prevents a numeric grade.
A planchet missing a section due to misalignment during the blanking process; a mint-made irregularity.
Chemical surface damage from contact with moisture, soil, or aggressive substances, causing pitting or roughness.
A coin that has received an unofficial later stamp or mark, often by a private party or for emergency use.
A coin with significant physical damage that prevents a numeric grade but does not disqualify certification entirely.
Corrosion confined to the rim or edge area of the coin, often from contact with another surface.
Damage on the edge (the third side) of the coin, distinct from rim damage on the obverse/reverse face.
General term for surface damage caused by the storage or burial environment of the coin.
A specific alteration where stars or similar small devices have been re-etched to enhance their visibility.
Letters, numbers, or marks intentionally cut, scratched, or engraved into the coin's surface.
A coin from which a mount or bezel has been removed, leaving evidence of the prior attachment.
A coin showing clear evidence of having been mounted in a piece of jewelry, with attached or removed mounting hardware.
A coin severely damaged or altered to the point that significant design or shape has been lost.
A minor pre-strike flaw on the planchet that remains visible on the finished coin.
A hole previously drilled through the coin that has been filled with metal to disguise the damage.
A coin with mechanical polishing that has altered or removed original surface detail.
A coin with design details that have been re-cut or sharpened by hand after striking.
A coin clearly removed from a jewelry setting, with traces such as mounting marks, solder, or rim alteration.
Damage concentrated on the outer rim of the coin, often from drops or contact with hard surfaces.
A coin whose rim has been filed or ground, often to remove evidence of mounting or to alter the diameter.
A rim that has been built up, smoothed, or otherwise repaired to disguise prior damage.
Linear surface marks deep enough to affect grade but not severe enough to disqualify certification.
A coin where parts of the surface have been smoothed by tools to hide marks or damage.
A coin showing visible solder residue from prior mounting or repair.
Localized spots or stains that have been chemically or mechanically removed, leaving altered surface in those areas.
Abnormal discoloration or staining that is not part of natural toning, usually from contact with a foreign substance.
A coin whose design has been re-cut or sharpened with engraving tools after striking, altering the original surfaces.
Repetitive marks across the surface caused by passage through a mechanical coin-counting machine.
A coin treated with a rotary wire brush to simulate mint luster, producing characteristic flow lines.
A coin with light directional cleaning marks from being wiped with a cloth or similar material.
Issues serious enough that the coin is returned without encapsulation.
An ongoing chemical reaction that is still attacking the coin's metal at the time of examination, not a stabilized historical surface.
A coin where a mintmark has been added after striking to create a more valuable variety.
A coin where one or more digits of the date have been changed after striking to imitate a rarer year.
A coin where the mintmark has been modified after striking to imitate a more valuable issue.
A coin whose surface has been intentionally modified after striking to conceal damage or simulate a different state.
A coin with unauthorized engravings or modifications of an indecent or vulgar nature.
A specific aggressive corrosion of copper-alloy coins, appearing as pale-green or bluish powdery growth that can keep spreading.
A normal coin intentionally damaged after the mint to imitate a genuine mint error.
A coin or medal where an added applied element has separated from the main piece.
Residue left behind by chemical dipping treatments used to remove toning or surface grime.
A coin where design elements have been re-engraved by hand after striking, altering originality.
Adhesive material left on the coin from prior mounting in albums, frames, or jewelry.
A coin whose date cannot be read with confidence, preventing reliable attribution and certification.
A coin whose mintmark cannot be read with confidence, preventing reliable attribution.
A legacy term for a coin with multiple or unspecified issues; superseded in modern catalogs by more specific designations.
A piece outside the categories the service accepts for certification.
A coin so worn or damaged that key identifying details are no longer present.
A coin coated with varnish or lacquer to "protect" it, which alters the surface and prevents normal grading.
A piece on which graders cannot reach a confident authenticity decision; held without certification.
A piece determined to not be a genuine product of the issuing authority; cannot be certified.
A piece that, for various reasons combined, cannot proceed through the certification process.
A coin coated after the mint with a layer of another metal, altering its surface and composition.
Contamination from PVC-based flips or holders, which release plasticizers that damage coin surfaces over time.
Actual surface damage caused by PVC contamination, beyond simple residue.
A coin previously contaminated by PVC that has since been cleaned, often leaving residual evidence of both issues.
A piece whose authenticity could not be confirmed with available evidence; not certified pending further review.
A coin where the mintmark has been removed after striking, usually to imitate a different or rarer issue.
Foreign material on the surface of unknown composition that prevents the coin from being graded as-is.
A coin where residue was present and has since been cleaned, with traces of both still visible.
Surfaces that are actively deteriorating or that may continue to change, making certification unsafe.
Look-alikes and post-mint damage that resemble mint errors but are not.
A coin whose surface has been physically modified after striking, often to hide damage or simulate an error.
A coin where part of the metal has been cut or filed after the mint to mimic clipping or other planchet errors.
A counterfeit coin manufactured to imitate a famous mint error and deceive collectors.
A normal coin that was intentionally damaged outside the mint to imitate a genuine mint error.
Damage that occurred after the coin left the mint. It is not a true mint error and is not gradeable as one.
A piece whose status as a genuine mint product cannot be confirmed and which therefore cannot be certified as an error.
Indicates an uncirculated coin; not an extra designation but part of the grade label itself (e.g., MS 65).
Learn how grades are assigned →Now that you know the vocabulary, see how the 1–70 Sheldon scale is applied.
