Celtic coins are those made by the Celtic tribes across Europe between the fourth century BC and first century AD. Initially they were mainly based on Greek coin designs and values, i.e. the Stater or its fractions. British Celtic coins were made between the late second century BC and the middle of the first century AD. Roman coins displaced this coinage after the Roman conquest of Britain.

Serious collectors of Celtic coins will probably be well aware of the Celtic Coin Index. Dr.Philip de Jersey of the Institute of Archaeology, Oxford, manages this index. It is a photographic record of the Celtic coins found in the British Isles. It contains over 30,000 records. The photographs of the later additions are of a high quality but some of the earlier images are not to this standard and are gradually being updated.

A search of the Celtic Coin Index (CCI) for fakes gives forty-five results. One of these is in the CCI's May 2004, "Coin of the Month" feature. It is shown across. It is believed to be a copy of an electrotype of a Stater from the British Museum. It is the fifth example of this type recorded in the CCI. The first example was recorded in 1962. These counterfeit coins are stated to be generally silvery in colour and light in weight. This last example weighs 2.6g.

The main pages of the CCI can be found at:

The May 2004, "Coin of the Month" with more details of this interesting counterfeit can be found at:

An October report from gives an impression of the type of circulating coin counterfeiting occurring in India. Three men were accused of manufacturing low-melting point, metal counterfeits. They were also accused, with an additional four men, of distributing the counterfeits. The police seized just over 3,000 counterfeit coins.

It would appear the metal was melted on a gas burner and cast into moulds . The moulds appear to have been vibrated with an electric motor to improve the quality of the casting. The police claim about twelve counterfeits a minute could be produced. It is assumed the metal used was a lead/tin alloy.

All the reports that we have, on circulating counterfeit coin, from the Indian media are of this nature. They are of relatively small-scale operations, producing cast counterfeits. This is in contrast to some of the Indian counterfeit banknote reports. These can be international in scope, in some cases dirty tricks by Pakistan's intelligence service have been alleged, and pose a much more serious threat to the Indian economy.

The Platinum Metals Review has recently published three papers investigating the history, manufacturing technique and authenticity of 19th century Russian platinum roubles. Coins held by Heraeus in Germany and Johnson Matthey in England were subjected to a series of scientific investigations.

The three denominations of platinum roubles were first issued by Russia in 1828. The Russian Government had declared a state monopoly on all dealings in platinum soon after the discovery of significant amounts in the Urals between 1819 and 1825. However they had to stop issuing further coins after 1846 as the world price of platinum fell due to supplies becoming available from Colombia. The coins were withdrawn and sent for refining. This means only a small number of genuine coins have survived. Later in the nineteenth century there were unofficial issues and counterfeits produced. Professor Christopher Raub records the total number of platinum coins produced between 1828 and 1846 in the first paper of the series as:

3-roubles       1,373,691
6-roubles            14,847
12-roubles            3,474

The findings on the coins are summarised below:

Coin        Date         Mass    Density             XRF Surface Analysis
                                                                    %Pt   %Fe   %Ir    %Rh   %Pd
Johnson Matthey
3-rouble  1828    10.35g    21.27g/cc  100%    trace    -       -            -
3-rouble  1834    10.16g    21.17g/cc  99.3%   0.7%    -       -            -
3-rouble  1835    10.31g    20.32g/cc  95.2%   4.8%    -       -            -
Heraeus
3-rouble  1842    10.27g    20.78g/cc  97.4%*  0.3% 1.7% 0.1% 0.1%
3-rouble  1844    10.37g    20.40g/cc  93.3%*  0.4%   -       2.5% 1.0%
Johnson Matthey
6-rouble  1830    20.70g    20.42g/cc  98.4%    1.6%     -       -            -
Heraeus
6-rouble  1830    20.64g    21.18g/cc  97.7%*  1.8% 0.5%    -           -
12-rouble 1832   41.34g    20.26g/cc  97.9%*  0.6% 1.0% 0.1% 0.1%

* Result calculated, %Pt = 100 - sum of other elements found. These are only semi-quantitative results.

It was considered that the Heraeus coins were produced from calcined chloroplatinate. The resultant platinum sponge being cold pressed, then heated to white heat and further compressed. The malleable metal was then hammered for fabrication. Coins produced by this process were considered to:

a. have a density less than that of platinum produced by a melt-solidification process;

b. possess a certain striated structure seen in micro-sections;

c. and, depending on their sintering, show a "snake skin" surface structure.

Professor Raub states that genuine platinum roubles contain iron up to 4 percent and iridium from undetected to 0.85 or 1.06%. The currently accepted value for the density of platinum is 21.45 g/cc. The densities of genuine platinum roubles vary between 20.03 to 21.32 g/cc.

It was concluded from the Johnson Matthey study that the 1828 3-rouble was forged and that the 1834 3-rouble is more than likely to be forged. The first conclusion was based on the purity of the platinum found, the second was based on x-ray diffraction data.

The papers concerned can be read at the Platinum Metals Review web-site at:

Number of common classes of euro counterfeits found per annum

The European Technical and Scientific Centre published its in the autumn of 2004. It gives information, unavailable elsewhere, on the types and sources of euro counterfeits.

The report states that, "Current statistics indicates an asymmetry between the quantity of counterfeits produced and the number seized or removed from circulation". ETSC estimated that over 2 million 50-cent and 1-euro counterfeits were put into circulation by two illegal workshops dismantled by the Italian police in 2002. Yet only 80,000 have been (mainly) seized or found in circulation.

50-eurocent counterfeit coins

Six new common (stamped) classes of 50-cent counterfeit coins were identified in 2003. These were mainly found in Italy with some in Austria, Germany and France.

The visual appearance of these new classes was described as, "relatively bad as compared to bicolour counterfeit coins". They were made of brass and bear the Italian national side. The quality of these classes was considerably lower than the one class found in 2002 that was related to the illegal Italian workshop dismantled in that year.

1-euro counterfeit coins

In 2003 counterfeit 1-euro coins were still being mainly found in France and Italy. The examples being found were still mostly related to the illegal workshop dismantled in Italy in 2002. Four additional common classes of stamped 1-euro counterfeit coins were identified by ETSC in 2003. A total of nine common classes of counterfeit 1-euro coins have been identified since the introduction of the euro coins.

The Greek police found two batches of counterfeit 1-euro coins in September 2003. The second batch consisted of 5,808 counterfeit coins. All the counterfeits were of the same type. The Greek police indicated they might have originated from Turkey.

The Italian authorities discovered an illegal counterfeit workshop on 29th October 2003 in Lumezzane, Brescia. It was set up to produce 1-euro counterfeit coins with Italian and German national sides. Thirty 1-euro counterfeit coins were seized plus materials and tools.

2-euro counterfeit coins

Five additional common classes of stamped 2-euro counterfeit coins were identified in 2003. A total of ten common stamped classes have been identified since the introduction of the euro coins. Within these common classes are a total of sixty-nine variants. The increase in the number of variants and the number of counterfeit coins found in circulation, see Newsletter No.2 prompted ETSC to state, "..that the counterfeiting activity is relatively intense".

The Italian authorities dismantled an illegal counterfeit workshop on 26th November 2003 in Villanova in the Venice area. The workshop was ready to produce counterfeit 2-euro coins.

298 counterfeit stamped 2-euro coins were found in Finland during October and November 2003. The Finish authorities traced some of these coins to a Finnair flight from Turkey to Helsinki.

Local class euro counterfeit coins

The ETSC local class counterfeit coins are generally cast counterfeits. The euro counterfeit coin national analysis centres, CNAC, created an extra eighteen local classes in 2003 to give a total of twenty-six local classes. These are generally 2-euro counterfeit coins and mainly found in Germany.

In May 2003 the Portuguese police seized 924 1-euro and 2-euro counterfeit coins and dismantled the corresponding illegal workshop.

Comment

ETSC created a total of twenty-six common classes of stamped counterfeit coins in 2002 and 2003. Theoretically these should equate to about twenty-six illegal counterfeit coin workshops. The national authorities dismantled five such shops in 2002 and 2003. Another large workshop was dismantled by the Spanish authorities in 2004. This means that at least fifteen to twenty workshops have not been discovered. There is some evidence that some of these may exist outside the euro zone.

Although the above may have a large margin of error it still indicates the euro zone police forces have a large job to do.

In his November 2004 "Coin World" column, Michael Fahey reports an increase in the numbers of gold counterfeits submitted to the ANACS for grading. He specifically mentions recently submitted counterfeits of Indian Head gold dollars (1854) and $3 coins (1885).

At the end of 2003 and the spring of 2004 dealers became aware of significant numbers of counterfeits appearing in batches of unclean Roman coins allegedly originating from Bulgaria. Bob Bischoff initially published information and images in an excellent article at http://members.aol.com/petronicoins/uncleanedfakes.html. Jim Phelps then wrote an article in the "Celator" in March 2004 and summarised this on the web at http://www.ruark.org/coins/ModernFakes/ . Finally there is another article with images covering similar ground at .

The "How the West was faked" website mentioned in Newsletter No.2 has changed its server and now can be found at .

There continues to be a steady stream of counterfeits mainly aimed at the USA market and originating from China. Examples of these can be found on e-bay in many different categories. They range from very crude cast counterfeits which would only fool those with no knowlege of coins to more convincing struck coins such as Trade dollars. An example of a supposed Elizabethan 1887? crown is shown across. It is a cast copy of the Elizabeth II silver anniversary crown with the 1977 date changed to 1877! Often with the cruder counterfeits the main profit appears to being made by overcharging for carriage.

In the second half of 2004 there have been reports of counterfeits involving: USA dime coins, German Oktoberfest tokens, Malaysia RM1 coins, Taiwan NT$50 coins and Canadian Toronto Transit Commission subway tokens. There have been no more reports of counterfeit Japanese 500-yen coins.

December 2003 was the last day the Brazilian stainless steel 1-real could be officially used. It has been replaced by the bimetallic 1-real first issued in 1998. The stainless steel coin was replaced because of the extensive counterfeiting of the coin. The Central Bank estimated that 444,000 counterfeit coins had been found. No counterfeits of the bimetallic coin had been found up to December 2003.

The new South African R5 coin was introduced in August. It will circulate along side its heavily counterfeited predecessor. The new coin is a bimetallic coin with an edge groove containing an inscription in relief.

This article attempts to describe the developments in the scientific examination of counterfeit coins since 1950. It is does not attempt to describe in detail the scientific techniques mentioned. It only describes the use to which they have been put. The aim is for it to be understandable to the non-scientist who is interested in coins.

In the Counterfeit Coin Newsletter No. 2 the story of the counterfeiting of the British gold sovereign in the 1950's and 1960's was sketched out. Since that time the scientific techniques available for examining coins have been transformed. In 1950 there were a group of classical technique available for examining counterfeit coins. These included visual examination, weighing, specific gravity determination, hardness testing, metallography showing the crystal structure of the coin and chemical analysis. These last two both involved the partial destruction of the coin. They were not usually considered practical especially when examining high value or rare pieces.

The procedures used by the British Royal Mint at that time, note 1, are illustrative of those used by other experts in the universities, museums and fledgling forensic science laboratories of the world. Examining the first groups of counterfeit sovereigns they relied heavily on the weights of the coins and visual inspection. They occasionally supplemented this with a gold fire assay on a representative coin from a batch to determine the amount of gold present in the alloy. The gold sovereign is made to a very tight tolerance in both weight and gold fineness. The counterfeiters' weight and fineness control was not to this standard and their products were obvious using these relatively simple tests.

The cupellation stage of gold assaying

Visual Examination

Visual examination of suspected coins has always and probably always will be one of the main weapons against the counterfeiter. In 1993 Sylvia Hurter, former chairman of the IAPN Anti-forgery Committee, wrote, note 2, concerning the "Black Sea Hoard" controversy ( http://www.snible.org/coins/black_sea_hoard.html), "What this imbroglio teaches us is that we should continue to rely on our eyes rather than always turning to scientific props." Although this position is extreme this controversy certainly shows that scientific evidence must be based on "good" science and viewed as part of the evidence and not the only valid evidence.

Visual examination can give clues as to whether the coin is made of the correct material by way of colour and brightness. It can show incorrect manufacturing procedures, such as a cast instead of a struck coin. Earle Caley of Ohio State University, note 3, made a good summary of some of these types of signs in an article in Numismatic Review in 1945. Casting technology has improved significantly since this article and not all the points are now relevant. Visual examination can also show stylistic anomalies, especially in counterfeits of ancient coins. It also allows the identification of die faults transferred to the counterfeit. This allows batches of counterfeits from the same source to be grouped together. It allows the identification of most low-grade counterfeits without having to use any sophisticated techniques.

Caley's review shows that high powered microscopes were being used for the visual examination of coins prior to the 1940's. However their use for examining coins was not widespread. The Royal Mint in the 1950's usually only used low powered x6 or x10 eyeglasses for examining suspected counterfeit coins although they possessed more powerful optical microscopes. The low powered eyeglass and the loop still retains a strong position with numismatists and for preliminary examinations. However the main tool in the visible examination of coins has become the stereomicroscope, note 4.

A typical stereomicroscope

The stereomicroscope has a relatively low magnification but provides a three dimensional image and a relatively wide field of vision. Another type of microscope used in this field is the electron microscope. This offers significantly greater magnifications but the colours it shows are not true colours. It can be used to view the crystal structure of the metal and artefacts on a similar scale, but it is my opinion that apart from these uses it is of limited use for counterfeit investigation. The electron microscope can be useful when used in association with a spectrometer, this will be dealt with later. The comparison microscope, where images from what is in effect two separate microscopes are brought together for comparison, had some limited use but digital images and computer software have now displaced this technique.

One part of the coin which counterfeiters usually take much less care reproducing is what has been called the third side, the edge. One feature not usually reproduced correctly is the number of notches on the milled edge. In the middle 1950s the Royal Mint started to use this as an important objective measure for authenticating sovereigns. Examining the files it would appear that they first learnt the technique from the one of the German mints. The counting of the notches was made easier by rolling the coin on plasticine and either counting the notches made using a travelling microscope or photographing the plasticine and then counting the notches on a photographic enlargement. In 2000 European mints were using a profile projector for the quality control of the shape of notches etc. and these mints are beginning to use this in the characterisation of counterfeit edges.

The technique of measuring notches

In the late 1950's the Royal Mint started to photograph the examined counterfeits. This was for record and reference purposes but also it allowed easy examination and comparison of coins for defects and die matches. These photographs allowed connections to be made between counterfeit coins seized in a number of different countries. Although photographic equipment and techniques have improve significantly since this time, the approximately four inch (about 100mm) diameter black and white photographs produced by the Royal Mint during the 1960's have not been surpassed for defect illustration. To a non-photographer this appears to have been due to the careful illumination that produced the minimum reflection and shadows. Since that time colour photography has become ubiquitous. Polaroid photography has come and almost gone and the continuous rise of digital photography is still with us. Many microscopes now have attachments to allow digital photographs to be taken and stored as an object is examined. The risk with digital photographs is that the image can be manipulated to "improve" evidence.

Relative density

In the 1950's the Royal Mint did not usually measure the relative density or specific gravity of suspected counterfeit coins. Although the technique is very old the first published attempts at quantifying the accuracy of the procedure for determining the fineness of gold objects was by Earle Caley of Ohio State University in the late 1940s and early 1950's, note 5. In binary alloys (i.e. mixtures of two metals) the larger the difference in relative density of the two pure metals in the alloy the better the accuracy possible with the method.

In 1956 Dr.J.Watson, the then Chemist and Assayer, wrote rather intemperately in an internal note, " It is the Royal Mint's opinion , .... that small differences in density are of no value whatever." The relative density was still not recommended in the Royal Mint's procedures in 1963 but the procedure had become firmly established by the early 1970's. This may have been due to the succession to the Chemist and Assayer position of the more open minded E.(Ernest) G.V.Newman. Later in the 1970's in his position as director of the International Bureau for the Suppression of Counterfeit Coin Newman made wide use of the technique.

The relative density is determined by weighing the coin first in air and then in a liquid of known relative density. Initially the liquid used was water. In 1970, to improve the accuracy of the technique, Hughes and Oddy of the British Museum, note 6, suggested its replacement with perfluoro-1-methyl decalin which had a lower surface tension and higher relative density. Other replacement liquids have been suggested since then but water is still widely used.

The techniques main advantages are that it is non-destructive and uses the whole coin eliminating any sampling errors. Oddy and Hughes explained the three main defects of the technique for determine the gold fineness of an alloy as:

(i) It can only be applied with great accuracy to binary alloys.

(ii) Corrosion products on the object.

(iii) Gas bubbles in the object.

The technique is currently usually used in counterfeit investigations not to determine the composition of a coin but for comparison against a known, genuine coin. It is relatively most reliable with struck gold coins, usable with high silver alloy coins but it use for cast, copper alloys is problematic.

Classical chemical analysis

Classical chemical analysis reached the peak of its use and usefulness by the 1960's. The techniques available for ancient coins were summarised by Caley in his book, "Analysis of Ancient Metals", note 7. The techniques for more modern alloys and coins are spread out over a vast array of books and journal articles mainly published up to the early 1970s. These techniques usually involved the dissolution of a significant sample of the metal alloy in an acid. The sample needed to be representative of the whole coin and to contain no surface corrosion. However because of the relatively large sample size used in these techniques micro-segregation in the coin was generally overcome. These techniques although often slow and time consuming offered great accuracy and precision. However they were generally poor in determining elements present at the trace level.

Since the late 1950s, 1960s, early 1970s analytical techniques have been transformed by a series of different instrumental techniques. The roll for the classical techniques has been gradually squeezed to almost zero. They are used in chemical education and perhaps in the analysis of standard materials but rarely elsewhere. This means that even when there may be an advantage in using one of the techniques there is nobody available who is trained and experienced in their use. The last significant publications of ancient coin analysis utilising these types of technique appear to have been by Lawrence Cope between 1967 and 1977, note 8.

In the 1970s the Royal Mint used a selection of these techniques for analysing low melting point white metal alloys. These lead/tin/antimony alloys are often used in cast counterfeits. Poor casting technique often produced significant segregation during solidification. This meant that the classical techniques using a large sample size produced more representative results for these alloying elements. The destruction of a portion of the counterfeit coin was not significant as a number of counterfeit coins were usually found in this type of prosecution.

Excluding gold and silver assaying it has not been possible to find any evidence that classical chemical analysis techniques are currently being used in counterfeit coin investigations.

References

Note 1: Royal Mint files deposited at the National Archive: MINT20-2317, 20-2318, 20-2319, 20-2320, 20-2321. These are titled, Counterfeit: sovereigns, and cover the period 1950 to 1959

Note 2: Sylvia Hurter, "The Black Sea Hoard", Bulletin on Counterfeits, 1993, vol. 18, no. 1, pp 34-35

Note 3: Caley, Earle R., "Methods of distinguishing cast from struck coins", Numismatic Review, 1945, 2, no. 4, pp 21-24

Note 4: Meng, Hsien-Hui et al, " A systematic procedure for the forensic examination of questioned coins with a face value of fifty New Taiwan Dollars, Forensic Science Journal (Taiwan), 2002, 1, pp 39-46

Note 5: Caley, Earle R.,"Validity of the specific gravity method for the determination of the fineness of gold objects", Ohio Journal of Science, 1949, 49, pp 73-82

Note 6: Hughes. M.J. & Oddy, W.A., "A reappraisal of the specific gravity method for the analysis of gold alloys", Archaeometry, 1970, 12, pp 1-11

Note 7: Caley, Earle R., "Analysis of Ancient Metals", book, published by Pergamon Press 1964

Note 8: Compiled by Oddy, W.A., "Numismatic bibliography of Lawrence H. Cope", Metallurgy in Numismatics, vol 1, 1980, pp 216-217

For a wide ranging view of many of the scientific techniques used to examine coins (especially ancient ones), I would recommend "Metallurgy in Numismatics, Volume 4" published in 1998 by the Royal Numismatic Society.