Sheldon coin grading scale

Example of an Early American Cent - the coins that inspired Sheldon to create a more precise grading scale. (Courtesy of the National Numismatic Collection, National Museum of American History [photograph by Jaclyn Nash].)

The Sheldon Coin Grading Scale is a 70-point coin grading scale used in the numismatic assessment of a coin's quality. The American Numismatic Association based its Official ANA Grading Standards in large part on the Sheldon scale. ^[1] The scale was created by William Herbert Sheldon.

Original Sheldon Scale (1949)

In 1949, the original scale was first presented in Dr. William H. Sheldon's Early American Cents, 1793–1814 titled "A Quantitative Scale for condition" as a way to grade Large cents. The scale is known today as the Sheldon scale. ^[2]

#	Grade
1	Basal State-1
2	Fair
3	Very Fair
4, 5, 6	Good
7, 8, 10	Very Good
12, 15	Fine
20, 30	Very Fine
40	Extremely Fine
50	About Uncirculated
60	Mint State
65	Mint State
70	Mint State

Adapted scale (1970s–present)

A selection of three Walking Liberty half dollars of various coin grades and years, ranging from AG (About Good) to AU (Almost Uncirculated).

By 1953 the original Sheldon scale had become outdated. It was not until the 1970s, however, that the ANA chose to adapt the scale for use on all US coins. ^[3] The scale used today is a modification of the original Sheldon scale, with added adjustments, additions, deletions, and modifications to it. ^{[4] [5]}

Note: Some early American coin varieties are almost always found to be weakly struck in places. This does not bring the grade of these coins down as in some cases no flawless coin exists for the variety. Early coins in general usually have planchet quality issues which depending on severity and market conditions can bring the grade down for other coins. ^{[6] [7]}

Circulated grades

#	Grade	Grade code(s)	Description
1	Poor	PO	Clear enough to identify, date may be worn smooth with one side of the coin blanked. Coins that are very badly corroded may also fall under this category.
2	Fair	FR	Some detail shows
3	About Good	AG	Readable lettering although very heavily worn. The date and design may be worn smooth.
4	Good	G, G4	Rims of the coin are slightly worn, design is visible, but faint in areas, with many parts of the coin worn flat. Peripheral lettering nearly full.
6	Choice Good	G+, G6	Rims of the coin are complete. Peripheral lettering is full.
8	Very Good	VG, VG8	Slight detail shows, with two to three letters of the word LIBERTY showing in coins with this feature.
10	Choice Very Good	VG+, VG10	Slightly clearer design-features, with five or possibly six letters of the word LIBERTY showing in coins with this feature.
12	Fine	F, F12	Some deeply recessed areas show detail. All lettering is sharp. The letters in the word LIBERTY show completely in coins with this feature, but may be weak. Moderate to considerable, but even wear throughout the coin.
15	Choice Fine	F+, F15	Slightly more detail in the recessed areas of the coin.
20	Very Fine	VF, VF20	Moderate wear on the higher surface features.
25	Very Fine	VF25	All lettering and major features are sharp. Light to moderate, but even wear is seen on the surface and high points of the coin.
30	Choice Very Fine	Ch.VF, VF+, VF30	All lettering and major features are sharp. Light, but even wear is seen on the surface and high points of the coin.
35	Choice Very Fine	Ch. VF, VF+, VF35	All lettering and major features are sharp. Light, but even wear is seen on the surface and high points of the coin. Traces of mint luster may show.
40	Extremely Fine/Extra Fine	Ex. Fine, EF40	Overall sharpness. Light wear seen at the highest points of the coin. Details of the coin are sharp. Traces of mint luster may show.
45	Choice Extremely Fine	Ch. Ex. Fine, EF45	Slight, overall wear is seen at the highest points of the coin (examples being raised features). All the details are full and very sharp. Mint luster may show only in protected areas of the coin's surface (Such as between the star points).
50	About Uncirculated/Almost Uncirculated	AU, AU50	Traces of wear at the highest points of the coin. At least half of the original mint luster remains.
55	Choice About Uncirculated	Ch. AU, AU55	Three-fourths of the original mint luster remains.
58	Choice About Uncirculated	Ch. AU, AU58	Almost all of the original mint luster remains

Uncirculated grades

A Walking Liberty half dollar in MS (Mint State) condition, graded MS66.

Mint State refers to a coin minted for regular distribution that was never actually put into circulation, i.e., it was never used for daily commerce; it is uncirculated. ^[4] Since individuals never used these coins to purchase goods or services, the coins were not handed from one person to another; they were not jumbled up with other coins in pockets or purses; and they were not repeatedly counted—and touched—by retailers and bank personnel. Consequently, uncirculated coins should not show signs of wear. ^{[lower-greek 1]}

In modern-day United States numismatics, collectors, coin dealers, and third-party grading services grade mint state coins using a number from 60 to 70 inclusive, with 70 representing a perfect coin with no visible blemishes. Coins in the lower grade range (60-63), are usually unworn, and may suffer from weak striking, bag marks and other defects that make them less attractive to the collector. Some Mint State early coins appear to be circulated due to weak strikes, die cracks, planchet problems, or metal quality. There are a few United States coins for which no mint state specimens exist, ^{[10] [11]} such as the 1792 silver dime, and the 1802 Draped Bust (Heraldic Eagle reverse) silver half dime. ^{[12] [13] [14]}

Adjectival grades for uncirculated coins

Coin dealers and individual coin collectors often use adjectives—with or without an accompanying Sheldon numerical grade—to describe an uncirculated coin's grade. The term Brilliant Uncirculated (often abbreviated as BU) is probably the most common—and the most ambiguous—of such adjectives. ^{[15] [16]} While Brilliant Uncirculated(BU) ought to refer to an uncirculated coin that retains its original mint luster, some equate BU with Uncirculated, i.e., they might refer to an MS-60 coin with little or no effulgence (brightness) as Brilliant Uncirculated. Along these lines, some numismatists argue that an unscrupulous subset of coin dealers mislead customers by using adjectival grades without defining their terms. ^[17] At the same time, there appears to be at least some consensus ^{[18] [19] [20] [21] [22] [23]} in the numismatic community for the following definitions.

Commonly Used (but unofficial) Adjectival Grades

Adjectival Grade	Equivalent Numerical Grade
Uncirculated	MS-60, MS-61, MS-62 [lower-greek 2]
Select or ChoiceUncirculated	MS-63
Choice Uncirculated	MS-63, MS-64
Gem Uncirculated	MS-65, MS-66
Superb Gem Uncirculated	MS-67, MS-68, MS-69
Perfect Uncirculated	MS-70

However, bear in mind that if a coin dealer advertises a coin as "Gem Uncirculated", it does not necessarily mean that a third-party coin grading company would assign an MS-65 or MS-66 grade to the coin. ^{[lower-greek 3]}

Numerical grades for uncirculated coins

#	Grade	Grade code	Description [5]
60	Mint State 60	MS60	Unattractive, dull or washed-out, mint luster typify this coin. There may be many large detracting contact marks (bag nicks), or damage spots, but absolutely no trace of wear. There could be a heavy concentration of hairlines (minute scratches to a coin's surface), or unattractive large areas of scuff-marks. Rim nicks may be present, and eye appeal is very poor. Copper coins may be dark, dull and spotted.
61	Mint State 61	MS61	Mint luster may be diminished or noticeably impaired, and the surface has clusters of small contact marks throughout. Hairlines could be very noticeable. Scuff-marks may show as unattractive patches on large areas or major features. Small rim nicks, striking or planchet defects may show, and the quality may be noticeably poor. Eye appeal is unattractive. Copper pieces will be generally dull, dark and possibly spotted.
62	Mint State 62	MS62	Impaired or dull luster may be evident. Clusters of small marks may be present throughout with a few large marks or bag nicks in prime focal areas. Hairlines may be very noticeable. Large unattractive scuff-marks might be seen on major features. The strike, rim and planchet quality may be noticeably below average. Overall eye-appeal is generally acceptable. Copper coins will show a diminished color and tone.
63	Mint State 63	MS63	Mint luster may be slightly impaired. Numerous small contact marks, and a few scattered, heavy marks may be seen. Small hairlines are visible without magnification. Several detracting scuff marks or defects may be present throughout the design or in the fields. The general quality is average, but overall, the coin is rather attractive. Copper pieces may be darkened or dull.
64	Mint State 64	MS64	Coin has good, overall average luster and even strike for the type. Several small contact marks in groups, as well as one or two moderately heavy marks may be present. One or two small patches of hairlines may show under low, (3-4x) magnification. Noticeable, light, scuff marks or defects may be seen within the design or in the field. Attractive overall quality with a pleasing eye appeal. Copper coins may be slightly dull.
65	Mint State 65	MS65	Coin shows an attractive high quality of luster and strike for the date and originating mint. A few, small, scattered, contact marks, or two larger marks may be present, and one or two small patches of hairlines may show under (5x+) magnification. Noticeable, light, scuff marks may show on the highest points of the design features. Overall quality is above average and eye appeal is very pleasing. Copper coins have full luster with original or darkened color.
66	Mint State 66	MS66	Coin has above average quality of strike and full original mint luster, with no more than two or three minor, but noticeable, contact marks. A few very light hairlines may show under (6x+) magnification, or there may be one or two light, scuff marks showing on frosted surfaces or in the field. The eye appeal must be above average and very pleasing for the date and originating mint. Copper coins display full original or lightly toned color.
67	Mint State 67	MS67	Coin has a sharp strike with full, original luster, May have three or four very small contact marks and a single, more noticeable, but not detracting mark. On comparable coins, one or two small single hairlines may show under (6x+) magnification, or one or two partially hidden scuff marks or flaws may be present. Eye appeal is exceptional. Copper coins have lustrous original color.
68	Mint State 68	MS68	Coin has a sharp strike with full original luster, with no more than four, lightly-scattered, contact marks or flaws. No hairlines or scuff marks show. Copper coins have lustrous original color. Eye appeal is exceptional.
69	Mint State 69	MS69	Coin has a sharp strike with full original luster, with no more than two small non-detracting contact marks or flaws. No hairlines or scuff marks are visible. Eye appeal is exceptional.
70	Mint State 70	MS70	The "perfect coin", as minted. Has no trace of wear, handling, scratches or contact with other coins from a (5x) magnification. Coins in this grade are almost non-existent in older coins with very few examples known. Copper coins are bright with full original color and luster. Eye appeal is exceptional.

Proof coins

See also: Proof coinage

Like circulated grades, proof coins are graded on the Sheldon scale from 1 to 70, and are preceded by the abbreviation ‘PF’ or ‘PR’ to distinguish them from circulation strikes. Proof coins graded 60 to 70 are mirrored to those of Uncirculated grades with the difference that the coin was not made for circulation. Proof coins with the grade of PR-63 are sometimes called "Choice Proofs". ^[25] Proof coins that are below the grade of 60 and show signs of circulation or mishandling have been classified as Impaired Proofs, these are not included alongside circulated coins as they were never issued or intended for circulation in the first place. ^[26] Coins in impaired proof condition include coin patterns which accidentally found their way into circulation.

#	Grade	Grade code(s)	Description
1 - 59	Impaired Proof	PR-45	Grades for impaired proofs mirror those for circulated grades.
60	Proof	PR, PR-60	Grade mirrors uncirculated grade. (See chart in above section)
63	Proof	PR-63	Grade mirrors uncirculated grade.
65	Proof	PR-65	Grade mirrors uncirculated grade.
67	Proof	PR-67	Grade mirrors uncirculated grade.
70	Proof	PR-70	Grade mirrors uncirculated grade.

Detracting coins

The following table shows coins that have detracting features. Coin dealers will normally grade these coins at or below the ones shown for that respective type, the grades here depend on how bad the issue or issues are. ^[27] Grading services typically label these coins as "authentic" with x grade "details" (ex: "EF details"). Coins that are uncirculated as mentioned above can not go below an MS-60 grade.

Type [27]	Grade usually given [27]	Description
Adjustment Marks	MS66 and lower	These include mostly early coins, excess metal (such as silver and gold) was cut from overweight coins to conform to weight laws. [28]
Planchet defects	MS65 and lower	Planchet defects such as die cracks or lamination are caused by flaws in a coin's metal before it was struck. Some "established planchet defects on early copper" may be more accepting by grading services. [29]
Striking defects	MS64 and lower	Examples include coins that are struck off center, have porosity, color impurity, or are weakly struck. The issue or issues are dependent on severity, and the resulting grade is caused by the "reality of the market". [7] (see entry below)
Unattractive toning	MS64 and lower	Depending on conditions. Coins that have very low eye appeal will be affected as the market value of these coins cannot warrant a higher grade. [30]
Carbon streaks	MS64 and lower	Carbon streaks are a flaw caused by environmental conditions. Some contributing factors include coin storage in a damp place, or exposure to cigar or cigarette smoke. [31]
Fingermarks	MS63 and lower	Oils exist in human fingerprints which can leave marks on the surface of a coin. These marks are usually the result of mishandling. [32]
PVC damage	MS63 and lower	Improperly stored coins in vinyl 2x2 flips, older albums, and coin holders. Green and gray streaks and/or spots appear on the surface of an affected coin. [33]
Black spots	MS63 and lower	Also known as sulfur spots, these coins are given dark brown to black spots by sulfur in the environment. These black spots have also been incorrectly dubbed as carbon spots, but carbon does not contribute to oxidation. [34]
Slide marks (aka "rub")	MS63 and lower	Slide marks are caused by improperly placing a coin into an album that contains plastic strip slides. The marks are given as the plastic slides or rubs across the surface of a given coin. [35]
Overdipping	MS62 and lower	These coins were dipped into a dilute acid solution too many times which stripped the coin's surface of luster. [36]
Cleaning marks	MS62 and lower	See: Cleaning (coinage)
Corrosion spots	MS62 and lower	Copper coins can turn green, while silver coins turn black from oxidation.
Wear	AU58 and lower	By definition an uncirculated coin will show no trace of wear.
Whizzing	AU50 and lower	These coins were gone over with a metal or wire brush to "enhance" the uncirculated details. Whizzing causes damage and wear to the surface of a coin which lowers its grade to "circulated" status. [27] [37]

Notes

1. Even longtime coin collectors sometimes do not understand the difference between uncirculated (mint state) and circulated coins. The key distinction is that circulated coins show signs of wear. In this regard, it may prove helpful to review the definition of wear from the Oxford English Dictionary: wear n. - "The process or condition of being worn or gradually reduced in bulk or impaired in quality by continued use, friction, attrition, exposure to atmospheric or other natural destructive agencies; loss or diminution of substance or deterioration of quality due to these causes." ^[8] [example quotation:] "This Scarcity will be farther increased by the Wear of Silver Coins, which has lessened their Weights considerably." ^[9]
2. Sometimes coin sellers apply the term Brilliant Uncirculated to coins in the MS-60 to MS-62 range, which may or may not be accurate depending on how one defines Brilliant Uncirculated (as discussed earlier). For example, PCGS defines Brilliant Uncirculated as a "generic term applied to any coin that has not been in circulation. It often is applied to coins with little 'brilliance' left, which properly should be described as simply Uncirculated." ^[20] Whereas Susan Headley states that a "... BU coin ... generally falls into the lowest MS grades [MS-60, MS-61, and MS-62] on the Sheldon scale." ^[19]
3. Of course, it is also true that if a coin collector owns a coin graded MS-65 by one of the leading third-party grading companies, there is a distinct possibility that if the collector removed the coin from the protective holder ('slab') and submitted the coin for grading to one of the other leading grading services--or even to the same service--the coin could come back with a different grade, e.g., MS-66 or MS-64. ^[24]

References

1. The Official American Numismatic Association Grading Standards for United States Coins. Bressett, Kenneth E.,, Bowers, Q. David,, American Numismatic Association. (7th ed.). Atlanta, GA: Whitman. 2013. ISBN   978-0794838249. OCLC   857586264.
2. James F. Ruddy (March 2005). Photograde: Official Photographic Grading Guide for United States Coins. Zyrus Press. ISBN   9780974237152 . Retrieved 2013-06-24.
3. Richard Giedroyc (15 November 2006). The Everything Coin Collecting Book: All You Need to Start Your Collection ... Adams Media. ISBN   9781593375683 . Retrieved 2013-06-24.^{[ dead link ]}
4. "The ANA Coin Grading Scale". American Numismatic Association . Archived from the original on August 19, 2022. Retrieved January 3, 2023.
5. "How United States Coins are Graded". www.pcgs.com/. Archived from the original on January 21, 2022. Retrieved 2013-06-16.
6. "Strike". www.coingrading.com. Archived from the original on June 26, 2022. Retrieved 2013-06-16.
7. Mike Sherman (April 19, 2016). "Difficult to Grade Coins – Part Three". Professional Coin Grading Service. Archived from the original on September 13, 2021. Retrieved October 19, 2017.
8. "wear" . www.oed.com (Oxford English Dictionary). Oxford University Press. Retrieved 2017-08-18.
9. Prior, Thomas (1729). Observations on coin in general With some proposals for regulating the value of coin in Ireland. Dublin, Ireland: printed by A. Rhames, for R. Gunne. p. 14. OCLC   938217893.
10. "Grading Draped Bust Cents". www.ngccoin.com. Archived from the original on July 4, 2022. Retrieved 2013-06-16.
11. Ken Potter, Brian Allen (21 March 2011). Strike it rich. Krause Publications. ISBN   9781440215780 . Retrieved 2013-06-16.^{[ dead link ]}
12. "Finest known 1792 Silver Dime brings $998,750 in Heritage's $28 million CSNS Auctions". www.ha.com. Heritage Auctions. May 9, 2016. Archived from the original on August 18, 2017. Retrieved 2017-08-18. The finest known 1792 Silver Disme AU50 PCGS ... realized an impressive $998,750 final price...
13. Bowers, Q. David. Sherman, Mike (ed.). "Draped Bust Half Dime". PCGS CoinFacts. Archived from the original on August 3, 2021. Retrieved 2017-08-18. Half dimes of this era are scarce, with 1802 being a prime rarity. Most surviving examples of various 1800-1805 dates are seen in lower ranges of condition, from About Good to Very Good or so. Fine specimens are not easy to locate, Very Fine pieces are still more elusive, and Extremely Fine coins are rare. Strictly Uncirculated pieces are extremely rare. Those that do come on the market are apt to be dated 1800. Uncirculated specimens dated 1801, 1802, 1803 and 1805 are exceedingly rare or non-existent. (No pieces were coined in 1804.)
14. Yeoman, R. S. (2016). Bressett, Kenneth; Bowers, Q. David; Garrett, Jeff (eds.). A Guide Book of United States Coins (Deluxe "Mega Red" ed.) 2017 ("The Official Red Book of United States Coins") (2nd ed.). Atlanta, Georgia: Whitman. pp. 627–631. ISBN   978-0794843922. OCLC   926062081. The majority of pieces surviving today are dated 1800, and nearly all of the AU or finer coins are of this date.
15. "How United States Coins are Graded". www.pcgs.com. Collectors Universe, Inc. June 12, 1995. Retrieved August 22, 2017. ... the designation BU (Brilliant Uncirculated) is frequently used to describe uncirculated coins. Because of the absence of a numerical grade, this term is ambiguous at best. Often, coins that are offered as BU may in reality be AU (About Uncirculated) by strict definition.
16. Enders, David. "Glossary". DavesCollectibleCoins.com. Archived from the original on September 27, 2022. Retrieved August 21, 2017. Brilliant Uncirculated - Refers to a coin which has not been circulated and which still retains the majority of its original mint luster. Sometimes "Uncirculated" and "Brilliant Uncirculated" are used interchangeably. However "Brilliant" [should] not be applied to a coin which has significant defects impairing its eye appeal or which is lacking in luster.
17. Reynolds, Greg (2011-04-20). "The Advertising of 'Choice' or 'Gem' Uncertified Coins". CoinWeek. CoinWeek, LLC. Archived from the original on July 5, 2022. Retrieved 2017-08-18. I am concerned that some advertisers in widely read 'print' coin publications are selling uncertified coins as 'Choice' (implied or thought to be MS-63 or higher), Very Choice (thought to grade MS-64), or Gem Uncirculated (thought to be MS-65 or higher) that do NOT come close to qualifying for such grades.
18. The Official American Numismatic Association Grading Standards for United States Coins. Bressett, Kenneth E.,, Bowers, Q. David,, American Numismatic Association. (7th ed.). Atlanta, GA: Whitman. 2013. ISBN   978-0794838249. OCLC   857586264. The ANA has not established equivalent official adjectives for the listings within the MS-60 to MS-70 range. Commercially, MS-70 coins are often called Perfect Uncirculated, MS-65 coins are often called Gem Uncirculated, and MS-63 coins are Choice Uncirculated.
19. Headley, Susan (May 18, 2017). "What Is a "BU" Coin?". The Spruce. Archived from the original on December 7, 2021. Retrieved August 18, 2017. Common adjective grading usually maps to the following Mint State grades: Uncirculated (MS-60, MS-61, MS-62): A technically uncirculated coin with abundant and noticeable defects such as bag marks and scrapes. It is usually accompanied by a poor strike and dull mint luster. Select Uncirculated (MS-63): An uncirculated coin with fewer deficiencies and better eye appeal been lower Mint State grades. Choice Uncirculated (MS-64): These coins have moderate distracting bag marks and/or very few, but noticeable, light scratches due to handling. Eye appeal will be good, but not outstanding. Gem Uncirculated (MS-65, MS-66): any uncirculated coin with only minor and light distracting marks or imperfections. Strike and eye appeal will be above average for the coin type.
20. "Coin collecting terms, slang, glossary". PCGS.com. Professional Coin Grading Service . Retrieved August 18, 2017. Choice Uncirculated - An Uncirculated coin grading MS-63 or MS-64. ... Gem Uncirculated - The adjectival equivalent of Mint State 65 or 66.
21. Enders, David. "Glossary". Dave's Collectible Coins. Retrieved August 18, 2017. Sheldon Scale - The modern numerical grading scale used for grading coins. The scale was created by American numismatist Dr. William H. Sheldon in 1949. This scale has become widely known and firmly accepted as the standard for coin grading in the US. The scale runs from 1 to 70 as follows: ... MS-60 - Uncirculated, ... MS-63 - Choice Uncirculated ... MS-65 - Gem Uncirculated ... MS-67 - Superb Gem Uncirculated
22. "What is an Adjectival Grade?". NGC.com. Numismatic Guarantee Corporation. Retrieved August 18, 2017. UNCIRCULATED is often paired with the additional qualifiers of BRILLIANT, CHOICE, or GEM. NGC considers BRILLIANT UNCIRCULATED to be any coins that would grade from 60-70 on the Sheldon Grading Scale. CHOICE UNCIRCULATED is considered to be any coins that would grade from 63 to 70 and GEM UNCIRCULATED is used for coins that would grade from 65 to 70.
23. "Coin Grading Tutorial". Heritage Auctions. Retrieved August 19, 2017. Coins with no wear at all are alternately referred to as Uncirculated (Unc.), Brilliant Uncirculated (BU), and Mint State (MS). ... It is important to note that Uncirculated and similar terms refer only to the fact that the coin has no wear. The presence or absence of bagmarks, toning (discoloration), or a strong strike does not affect a coin's Uncirculated status, although such things can affect the numerical grade of the coin. ... Uncirculated (MS-60, 61, 62) ... Although most price guides will give a price for coins in MS-60 condition, in many cases this is a very unusual grade, with typical uncirculated pieces often grading somewhere in the MS-62 to MS-64 range depending on the series. Select Uncirculated (MS-63) ... Choice Uncirculated (MS-64) ... Choice Uncirculated is sometimes used to refer to a coin grading MS-63. Gem Uncirculated (MS-65, 66) ... Superb Gem Uncirculated (MS-67, 68, 69) ... Perfect Uncirculated (MS-70): An utterly flawless coin.
24. Bowers, Q. David (2012). Grading Coins by Photographs (2nd ed.). Atlanta, Georgia. p. 1. ISBN   978-0794836870. OCLC   879642085. ... grading is, always has been, and will forever admit of a generous proportion of, old-fashioned opinion. What is Gem Uncirculated or Mint State-65 to one expert can legitimately be viewed as a lower grade, MS-64 by another expert, and MS-66 by yet another. This is because grading is interpretive, not an exact science.
25. "What Are Proof Coins? What Should You Know About Them?". www.coinnews.net. 2007-09-14. Retrieved 2014-03-05.
26. "Official ANA Definition of an Impaired Proof". coins.about.com. Retrieved 2013-06-16.
27. Ken Bressett and A. Kosoff. Official A.N.A. Grading Standards for United States Coins Fifth Edition. American Numismatic Association. p. 34.
28. Steve Roach (July 19, 2018). "Heavy adjustment marks can shave market value". Coin World . Archived from the original on September 4, 2020. Retrieved December 31, 2022.
29. Steve Roach (August 13, 2019). "Market Analysis: When a planchet defect is not unusual". Coin World. Archived from the original on November 27, 2021. Retrieved May 16, 2023.
30. Mike Sherman. "Toning. Does it help, or hurt the value of a coin?". Professional Coin Grading Service. Archived from the original on November 11, 2020. Retrieved October 19, 2017.
31. "Grades multiplied over years". Numismatic News. October 16, 2017. Archived from the original on December 2, 2022. Retrieved October 19, 2017.
32. "Insidious Fingerprints". Numismatic Guaranty Company . March 17, 2008. Archived from the original on July 31, 2021. Retrieved December 31, 2022.
33. "PVC Damage on World Coins – What It Is & How to Avoid It". CoinWeek. October 24, 2016. Archived from the original on June 28, 2017. Retrieved October 19, 2017.
34. "NUMISMATICS' GREATEST MISNOMER: CARBON SPOTS". www.coinbooks.org. April 18, 2014. Archived from the original on March 30, 2023. Retrieved October 19, 2017.
35. "Glossary of Coin Terms". Heritage Auctions. Archived from the original on November 16, 2022. Retrieved May 16, 2023. Album slide marks: Lines (often parallel) imparted to the surface of a coin by the plastic "slide" of an album, mostly found on proof coins.
36. Thomas E. Hudgeons, Jr. (11 June 2013). The Official Blackbook Price Guide to United States Coins 2014, 52nd Edition. Diversified Publishing. ISBN   9780375723490 . Retrieved August 25, 2017.
37. "Counterfeit Detection: Take a Look at Whizzed Coins". CoinWeek . December 21, 2022. Archived from the original on May 16, 2023. Retrieved May 16, 2023.