Bagmark: Nicks and scrapes generated when coins in a Mint bag jostle against each other. Almost all “classic” coins have bagmarks.

Business strike/Circulation strike: a coin minted for the primary purpose of serving as a medium of exchange in commerce.

CAC--Certified Acceptance Corporation:  independently verifyies those  NGC and PCGS coins submitted to CAC which are “solid for the grade” or better. CAC provides a “sight-unseen” buy offer on the coins that it endorses

Cameo: The first coins minted by a new die pair, whether circulation strike or proof coins, often demonstrate a frosted, cameo appearance on the main design devices.

Certification Service: Independent experts authenticate and grade coins submitted to them. PCGS, NGC, ANACS, and ICG are currently the major certification services, also known as grading services

Certified coin: Housed in a tamper-proof plastic case (or “slab”), these coins have been authenticated and graded by experts.

Choice Mint State: a better-than-average Mint state coin. Some bagmarks, and minor flaws may be present.

Cleaning coins: a commonly made mistake! Collectors desire coins that are original. Much of the value of a coin vanishes if it is cleaned.

Coin Collector: The “joy in the journey” for this person is gathering coins in the area he has chosen to collect that he did not previously own, or that upgrade his collection.

Coin Investor: This person views his coins primarily as an investment that he expects will experience financial appreciation. Historically, coins that represent high quality have generally done so.

Coin Mentor: In the rewarding and enjoyable hobby of coin collecting, finding a like-minded collector willing to share his experience with a neophyte collector greatly helps the beginner as he learns and advances in his hobby.

Coin publications: ”Coin World” and “Numismatic News” are weekly publications dealing with coin collecting; “The Numismatist” is a monthly publication put out by the American Numismatic Association.

“Collvestor”: This person has “a leg in each camp.” He collects coins for the joy the hobby brings him, but aims to garner a profit when he or his heirs sell his coins.

Conservation: Very carefully and professionally done by experts, “conservation” restores shipwreck coins, etc. to original condition, with none of the visible alteration to the coins’ luster or surfaces that “cleaning” causes.

Deep-Mirror Prooflike: The first few circulation-strike coins struck from a new die pair will not only often demonstrate “cameo” contrast on the main design elements, but will often have mirror-like coin fields as well. Deep mirror prooflike (DMPL) coins are scarce and widely desired.

Dies: The design of a coin is impressed into obverse and reverse dies which stamp out coins at the Mint.

Eye Appeal: The overall visual impact of a coin, encompassing luster, bagmarks, strike, and (perhaps) visual appeal of toning. Recognized immediately without magnification and quite universally appreciated by the coin’s viewers.

Field: the area surrounding the central coin design devices, on both obverse and reverse.

Gem Mint State: an above-average uncirculated coin with very few visible imperfections

Grade: Based upon the Sheldon Scale (See below), the grade of a coin expresses the degree of its wear if circulated and the coin’s quality if uncirculated

Grading Guides: Books providing pictures of coins in the various grades of the Sheldon Scale (See below) to help the coin buyer determine the grade of his coin.

Grading Service: See “Certification Service.”

“Greysheet”: The wholesale pricing guide to all U. S. coins, and a reference used by virtually all coin dealers and advanced collectors, officially titled  “The Coin Dealers’ Newsletter”

Hairlines: Often visible on a silver or gold coin that has been “wiped” with a jeweler’s cloth, hairlines are a detracting factor in a coin’s grade.

High Points: Usually the coin’s central design devices and the first place that circulation wear will show on the coin

Luster: The reflective surfaces of a newly-minted coin. Rotated and tilted  under a light, the natural luster of a coin will “shimmer” and be a major component of the coin’s eye appeal

Magnification: Looking at a coin with the naked eye while rotating and tilting it under a light is the first step in evaluating a coin. The second is to look at the coin under magnification, with 5X magnification powerful enough.

Mint State/Uncirculated: Synonymous terms to describe a coin that has full, original Mint luster and no wear visible on the coin’s high points.

Modern U. S. Coins: Coins made after 1964, usually with no precious metal content, often very beautiful, typically made in large enough quantities to more than satisfy demand and (proof coins especially) produced in near-perfect condition, rarely worth paying a premium for in “perfect” condition.  

N.G.C.: Numismatic Guarantee Corporation, founded in 1987 and one of the two premier third-party authentication and grading services in today’s coin market

Numismatic organizations: The American Numismatic Association (the A.N. A.) is the largest national organization with close to 30,000 members. Almost every large city has one or more local coin clubs. All offer educational and social opportunities to coin collectors at their regular meetings.

Numismatics/Numismatist: We can informally say “coin collecting”/”coin collector” here. Technically, numismatics is the study of the history, art, minting process, and other aspects associated with coins, and a numismatist engages in that process of study.

“Numismedia”: A wholesale pricing guide along with the “Greysheet” that provides accurate pricing information to the dealer and advanced collector

Patina/Toning: Refers to the natural process by which silver and copper coins interact with gases commonly found in the air we breathe, i.e. hydrogen sulfide, and form a layer of color(s) on the coin’s surface. Often quite attractive, rarely something that should be removed since the coin would lose part of its “originality.”

P.C.G.S.: Professional Coin Grading Service, formed in 1986 and one of the two pre-eminent third-party coin authentication and grading services in today’s coin market, along with N. G. C.

Population Report: Submission records of the date, denomination, Mint, and coin grade kept by the major third-party authentication and grading services. Provides a fairly accurate picture of the relative rarity of particular coins, although not every coin of a given date has been submitted to the services, and (occasionally) some have been re-submitted.

Price Guides: Other than “The Greysheet” and “Numismedia,” price guides tend to list (high) retail prices and are of primary value in determining relative worth of particular coins rather than “what a coin is worth” should one want to sell it

Prooflike coin: a circulation-strike coin that is among the first coins struck using a new die pair. Often with cameo devices and mirror-like fields not quite as deeply reflective as deep-mirror prooflike coins.

Raw” coin: a coin not authenticated and graded by one of the major authentication and grading services and thus not encased in a plastic “slab” by any grading service

Rim: the edge of a coin, on precious metal coins with reeding to make obvious any attempt to file off some of the precious metal

Sheldon Scale: Developed in the 1940s by Large Cent collector and researcher Dr. Sheldon to express the ratio between wear on a coin and its values relative to others in different conditions/grades. The Sheldon scale goes from 1-70, with 1 representing a “Poor” coin so worn as to be barely identifiable and 70 a “perfect” coin, with no flaws visible even under magnification

“Sight Seen”/”Sight Unseen” buy offers: Normally in numismatics, no dealer or collector will offer as much for a coin “sight unseen” as for one “sight seen,” even if the coin has been encapsulated and graded by one of the major grading services. This is due to the degree of subjective variability inherent in two coins ascribed the same grade, since no two coins are perfectly identical.

“Slab”: Colloquial term in numismatics for a tamper-proof plastic case into which one of the major third-party authentication and grading services has sealed a coin after authenticating and grading the coin.

“Slider”: Describes a coin that shows a teeny bit of circulation wear on its high points, from, e.g. “sliding” across a store counter or two in one of the very few times it was spent into the economy

Strike: Degree to which the high points of the coin’s design show all of the design details. Strike can be adversely affected by overused, worn dies or by dies placed a small degree farther apart than necessary by Mint employees desiring to maximize die pair life.

Toning: See “Patina/Toning” above

Type coin: A type coin is one of a particular coin series chosen by a collector to represent an entire series in his collection rather than trying to get every example of that coin series that was minted.

Wear: Through circulation in the economy (or occasionally through improper storage where coins have been allowed to rub against other coins or a storage surface), the original mint luster of a coin will wear off, starting first at the coin’s design high points. This loss of luster defines a circulated coin, with the degree of luster loss being an important factor in the coin’s grade.