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FORVM`s Classical Numismatics Discussion Board  |  Numism  |  For the New Ancient Coin Collector (Moderators: wolfgang336, Stkp, Lucas H)  |  Topic: Some simple observations on ancient coin flans 0 Members and 1 Guest are viewing this topic. « previous next »
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Author Topic: Some simple observations on ancient coin flans  (Read 21160 times)
rover1.3
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« on: February 22, 2013, 06:38:22 am »

A discussion about the typical flan for each type, period or mint, about some of the flan's basic characteristics is something which will not only help with the authentication
but also the better understanding and appreciation of each type, period, mint or even region as a whole. One could say that the fabric is the "heart" of each type.
I am not particularly good at reading technical matters, much less good at describing them and this is mainly because of the language.
For me, these and similar things are much easier to observe than explain in English, my second language. Be sure, it takes me a long time to write these posts.
A second problem which arises for me here is that my own interest is limited to what we call "Greek coins" and among them Hellenistic coins being my main field.
Undoubtly, some of the flan characteristics are common to many types from different regions or even different eras; flan preparation methods depended surely on the technology available at the hands of the people of a specific mint at the time of the issue of the coins but it is beyond doubt that specific methods, which had been characterized as succesful somewhere, earlier, continued to be followed by other mints at later periods, although the available technology of these later times might have been more advanced. I find the subject both important and interesting and I will try to make a start with a brief description of the flans often found on Seleukid AE's.

I hope others here more knowledgeable than I am, with the will to share, talented observers with the ability to express themselves with accuracy on such subtle but extremely important matters will follow and make this thread useful, making corrections or additions to those which will have been written here, and/or post their observations on the types and areas of their own interests.

Let's stay on topic and avoid "nice coin" and similar chat, "noisy" posts. Let's keep it simple and avoid entering into labyrinthine details, which often opens these chaotic and
disputed matters of controversy. Let's keep it into the basics so that the new collectors will be able to follow and be aware of how important the issue of the flan is.

An important thing to remember is that even coins of the same type may vary on the degree they show these flan characteristics. Some coins may exhibit some but not all of these characteristics. We are talking about ancient coins, one can't expect absolute uniformity in anything which has to do with antiquities and ancient coins.
New collectors will probably look for these characteristics on their own coins, and that is a good thing to do, but they should not worry if their coins don't obey all these "rules".
We have said it many times : Each ancient coin is unique and that sense of uniqueness is what we love.
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rover1.3
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« Reply #1 on: February 22, 2013, 06:40:40 am »

Seleukid AE's are frequently on beveled flans, their blanks were most probably cast in open, shallow bowl molds.
Usually, it is their obverses which are slightly larger than the reverses, (pic.1) but the opposite is common as well. (pic.2)
Which side would be the broader I assume, from my observation, was probably a random choice, left to the hands of the people who struck the coins and not of any significance. Of course, this is something anybody can add a thought to.
Seleukid AE's bear legends on their reverses, these legends often appear incomplete when the reverse happened to be the smaller side.
Generally, flans on the Seleukid AE's can be characterized as "tight"; incomplete designs and legends are common; badly centered coins are common too.
Many types bear center "dimples" (pic.3). Much has been written on these.
The cast flans of the Seleukid bronze coins often bear remnants of sprues from their connection prior to the strike. (pic.4) That was common to other ancient coin types as well from
various eras and regions. The separation of cold flans one from the other sometimes has left flans with damaged parts of their bodies. (pic.5)
Some Greek issues from Sicily are characterized by similar looking casting sprue remnants, (5th cent. BC Himera and Syracuse Hemilitron AE's among those well known), and often this is considered to be a good sign of authenticity.
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« Reply #2 on: February 22, 2013, 08:42:18 am »

The serrated edge Seleukid types are particularly remarkable. With bottle cup appearance, most probably for decorative only reasons. (pic.6)
Although these specific flan characteristics of the Seleukid AE's, which I described above, are observed on many types from the Seleukid mint of Antioch, types which modern
evidence places to other Seleukid mints show them as well.
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Lloyd Taylor
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« Reply #3 on: February 25, 2013, 08:55:39 pm »

I just received this one....  what a great goat!

Look at that edge seam I hear people say!

It is indicative of authenticity in this case, as the bronze flans were cast in a two piece mold, as was common practice at the time. In this instance the sides were mismatched prior to the molten bronze pour... so not everything with an edge seam is fake.... you need to understand the fabric of the coin and the manufacture process of the type to make any meaningful determination.
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rover1.3
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« Reply #4 on: February 26, 2013, 05:09:59 am »

Thank you Lloyd, exactly what I was looking for. Hopefully, new collectors will benefit from the discussion and start realizing the significance and importance of the fabric.

I think its fair to say that in the 4th century BC, the Persians tended to use more flat faced reverse dies than the Greeks whose reverse dies tended towards a slightly
hemispherical form which gives rise to a more concave reverse. Exceptions occur e.g. at Salamis and the Phoenecian mints the early Alexanders tend towards parallel obverse and reverses reflecting the prior Persian influence.

I think it is safe to assume that the slight concave reverses of Babylon tetradrachm emissions of Alexander's, Seleukos' I (in the name of Alexander and the later in the name of Seleukos) are a good and steady guide. The emissions from Babylon are characterized not only by their especially beautiful, often idealized style, but also by their sculptural obverse relief as well. Probably, it was exactly these concave reverses -along with the finely engraved dies and the obvious care of the mint workers- which had as a result the obverse relief to be significantly high. The concave reverses contributed to the transposition of metal to the center, "pushing" the obverse relief higher.

Regarding the cast flans and the kind of their manufacture, the picture below from Numiswiki is useful for the understanding of the matter.
The spure(s) remnants on coins give(s) a fairly good idea about which method was used.
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« Reply #5 on: February 26, 2013, 05:59:33 am »

Another key feature of coin flans is whether they are made in one-sided or two-sided moulds, and if in two-sided moulds, was the impression in one side or on both sides, and is the mould impression rounded or conical. The pictures below the message show a range of possibilities (adapated from RRC). These distinctions are particularly evident in thick coins, but in principle any coin could be looked at to see if it can be determined what is the type of mould.

fig.A shows a simple one sided mould. There may be sprues, or there may not - the "not" case implies a blob of metal was poured into the cavities, one flan at the time. The "sprues" case implies the cavities are all linked up. It's my belief that a lot of small denomination silver flans were made this way.

fig.B shows a two-sided mould, with a flat face on one side, and conical sides. This was more often used on struck bronze Republican coins of 218 to 210 BC, and from 110 BC to 95 BC. Because of the flat side, the other side of the mould is necessarily twice as deep. Because of that, sloped conical sides are often used to make sure the flan can be extraceted from the mould. This type of mould is dramatically shown in the picture below: the obverse is a good 6mm smaller in diameter than the reverse, with smaller devices, and the conical shape of the flan is very evident.

I've observed that these conical two-sided flans were only used in periods where teh coinage was in general of a very high quality, so it's clearly a more difficult way to make a coin flan.

fig.C shows a two-sided mould, conical sides.

fig.D shows a two-sided mould, rounded sides, which is the most usual type for Republican bronzes. In this case, the two sides are not perfectly aligned, and you can see an offset. This is particularly obvious in second century BC Republican asses. Here are two such offset flans, both incidentally from the same coin series, which is a key point: flan manufacture is often a key distinguisher.

In general I think insufficient attention has been made to flan characteristics; they are rarely recorded in catalogues, yet I think we might learn a lot about mint techniques and it may be of help in arranging coin issues. I've observed one coin series (RRC 106, staff and club bronzes from Luceria), where the As and Semis are the same diameter and were made using the same moulds. How? The As was made in a type C mould (two-sided, conical). The Semis used only one side of the same mould, i.e. type B, against a flat plate! On average, due to separatation between the moulds, the semisses of that series weigh about 60% of what an As weighs. Clearly this idea of producing very broad thin semisses with conical flans was a Bad Idea, because there's only one series it happens with. One observes and one learns. Someone should write these things down one day.

Studies of flans shows that good pictures are not always enough - I need to look at the coins from the sides to see how they were made, and thus to handle them in person.
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« Reply #6 on: February 26, 2013, 06:48:15 am »

I want to show another flan oddity, on the Victoriatus below.

The sprues are untypical, with a twisted shape on one side and a crack on the other side, and there's no evidence of any edge marks on the flan on this or any other coin of this type. Furthermore, on some coins of this type, a microscopically thin hair-line is visible on the surface of the coin, joining the two sprues, both on the obverse and the reverse. This particular coin is too strongly struck to show the hairline; but when visible, the hairline is the clue to the flan.

This flan was spherical, made by casting globes of metal (presumably in double-sided moulds) with thin sprues; once the sprues were removed, the flan was randomly placed on the die and struck. As it was a ball, the sprues were not necessarily at the edges but might be anywhere on the coin, obliterated by the strike. However the join-line between the moulds must always intersect the edges at exactly two points, 180 degrees from each other. So what looks like sprues are not sprues at all, but marks the interface between the two sides of the moulds, where they were not exactly aligned.. The hairline that I mentioned as visible on some coins is that interface between the moulds running across the coin. If this explanation is tough to follow, then imagine a type D flan but with hemisperical depressions, making a globule that is then struck in a random direction. Look at the diagram below: where the edge-line of the globe intersects the edge of the coin, you get a small crack or protrusion (not actually a sprue), and perhaps a visible line connecting the two protrusions/cracks across the coin face, the vestiges of the line on the globe where the moulds joined.

This needs you to think in 3 dimensions. So you may get a headache! NB the coin is exceptionally thick and high relief, which makes sense if we believe it was struck from a spherical flan.
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Lloyd Taylor
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« Reply #7 on: February 26, 2013, 01:31:35 pm »

Fascinating stuff!

I'd never given much thought to the consequences of a spherical flan manufacture process and your explanation turned on a light bulb with respect to the fourth century BC sigloi of Byzantion. I have the example below which has what I always thought to be a ragged one sided casting sprue. A lot of these coins of Byzantion exhibit this in various forms and to varying degrees, but equally striking (pardon the pun) is the  massive variability in an irregular flan shape. I always had trouble explaining the latter. The flattening of a spherical flan during striking explains all the observed phenomena.

Thanks for the great explanation which "turned on the light bulb" for me.
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Lloyd Taylor
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« Reply #8 on: February 26, 2013, 01:45:15 pm »

.....This needs you to think in 3 dimensions. So you may get a headache! NB the coin is exceptionally thick and high relief, which makes sense if we believe it was struck from a spherical flan.

The light bulb also now illuminates for this one... fourth century BC Neapolis where again we see the same relic "sprue" and with a similar thick fabric that bears with rounded soft edge/circumference that is consistent with the even squashing of a sphere between the dies (or possibly the result of some pre-strike processing and flattening via a nicely centered and evenly directed hammer blow?).
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Lloyd Taylor
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« Reply #9 on: February 26, 2013, 02:09:13 pm »

Some silver coins, particularly those of Medieval origin typically show a fabric that is partially the result of post-strike adjustment, via clipping to bring them below the weight standard ( the mints of the time never issued overweight silver coinage - underweight was preferred by these nickel and dimers!).

Two examples are shown below for Trebizond (showing the edge nibbled away by cutting with shears) and Ragusa (where the whole circumference shows evidence of trimming by shears).

The tool marks left by the iron shears used to trim the coins can resemble edge filing, but this is not a sign of fakery, rather it is the result of a mint weight adjustment process!
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Andrew McCabe
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« Reply #10 on: February 26, 2013, 03:11:17 pm »

This is turning out to be a great thread (I can already see it being stickied..), thanks to Nikos for starting it. So, for the sake of completeness, I'll throw in other flan-manufacture aspects as I think of them

First the "Stannard Al-Marco Gouge". Rough gouges appear on many Roman silver coins (example below). What is not generally understood for the new ancient coin collector, is that these were applied for weight control to the FLANS before striking, and are not the result of later damage. What is not often understand by even experienced collectors is that the flans were not weighed individually, but rather a batch of say 84 flans was made from, say, 13 ounces of silver, pouring them by hand into open moulds. Once the last few flans were reached, depending on how much silver was left, the later flans might be randomly a little heavy or light. Then the whole lot of 84 flans were put on a scales, and random flans were taken out, one by one, gouged, and thrown back in the scale until the batch weighed precisely 12 ounces (1 pound). Why do it this way rather than weigh individual flans? Because it's much much quicker, and it ensures that the random process of making individual flans doesn't result of you being short of the required number of denarii once you reach 12 ounces, or having a lump of silver left over after you've already made 84 flans. It's a brilliant control mechanism.

In Clive Stannards own words: Ancient mints sometimes adjusted weights by gouging a sliver, occasionally slivers, of metal from the face of a flan, before striking the coin. The results are characteristic and easily recognizable. Examples in silver are known from Lycia, Paeonia (King Adoleon), Velia and the Roman Republic, and there is a gold example in the coinage of Constantine I. This coin below is a clear example of a gouged piece.

The frequency of the use of gouging in the Roman Republic makes it possible to study whether weight adjustment was carried out al peso (which means that each individual flan was brought within the tolerances of the weight standard for the issue), or whether it was done al marco (which means not paying too much attention to the weights of individual coins, but ensuring that a fixed number of flans were made from a fixed weight of metal). This question can be investigated by looking at the histograms of large number of denarii, in issues known to be use gouging. In al marco, adjustment, a block of flans is cast a little heavy. The right number of flans for the desired weight of coins is counted out (and the overall weight will, of course be, too heavy). Flans that look heavy are successively picked out one by one, without too much attention to the weight, and a sliver of metal is gouged off. The gouged flans are tossed back into the block, until the overall weight is reduced to the right overall weight. The following figure models this process. As a result of adjustment al marco, the histogram is negatively skewed (the size of the upper leg has been reduced), and has high kurtosis (the centre of the histogram is higher than a normal distribution.)

8,649 denarii from between 144 and 43 BC were checked, to identify issues with gouging. 1.34% of all the coins looked at were gouged. The weight histograms of 4,587 Roman Republican denarii in the issues known to be gouged was negatively skewed, with high kurtosis, showing that they had been adjusted al marco. In these issues, 2.53% of the coins showed signs of gouging.

from Clive Stannard, "The adjustment al marco of the weight of Roman Republican denarii blanks by gouging, in M.M. Archibald and M.R. Cowell (eds), Metallurgy in Numismatics, Volume 3, pp. 45-70, London, 1993
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« Reply #11 on: February 26, 2013, 04:28:38 pm »

The "Stannard Al-Marco Gouge".... another  great explanation and a new insight for me that I think has relevance to the Alexander issues of Mithradates VI from Odessos on the period ca 80-70 BC (https://www.forumancientcoins.com/gallery/displayimage.php?pos=-86180).  A frequent minority of the coins of these emissions, which bear a portrait of Herakles with the features of Mithradates, bear curious rectangular gouges roughly centered on the obverse of the flan in the region of the ear and cheek of Herakles. Two examples are posted below.

I'd always interpreted this rectangular punch and gouge as some sort of bankers mark reflecting circulation in a military camp environment. I'm not so sure of that now, as the general rectangular form often appears overprinted by the strike. Al-Marco adjustment now seems to be a more likely explanation, with a sharp rectangular punch used to delimit the area from which a sliver of silver was gouged.  

This mint practice would be consistent with the fact that we find this fabric on only a very limited and specific range of Odessos output (those bearing Herakles with the features of Mithradates) produced when the mint was under the influence of Mithradates VI.  This may reflect the exigencies of rapid production in the time of the Mithradatic War which was being waged at the time of issue. After the war and pressure on the mint passed, then the mint reverted to the more usual but labor intensive practice of individual and specific flan weight adjustment.
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« Reply #12 on: February 26, 2013, 04:38:26 pm »

Lloyd I don't think those marks on the tetradrachms are Stannard gouges. There's not enough metal removed. The gouges need to dig out a chunk of metal not just make a stamp. But Stannard gouges do occur on some Greek coinages.
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Lloyd Taylor
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« Reply #13 on: February 26, 2013, 05:02:23 pm »

Lloyd I don't think those marks on the tetradrachms are Stannard gouges. There's not enough metal removed. The gouges need to dig out a chunk of metal not just make a stamp. But Stannard gouges do occur on some Greek coinages.

You may be right, but I have seen much deeper examples where a quantity of metal appears to have been removed.  I'll see if I can locate images of such examples. Many also show evidence suggestive of overstriking of the punch with interference between the design elemant and punch/gouge apparent.
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« Reply #14 on: February 28, 2013, 12:21:20 pm »

This is an excellent thread.  It would be great if someone would turn it into a wiki entry.  There is a very simple entry for "flan" that could be used as a platform.

Shawn
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« Reply #15 on: March 07, 2013, 07:05:36 am »

I agree.  This certainly is at least a Sticky grade thread.  It was mentioned that there are coins that should have an edge seam due to their method of flan manufacture.  There are also issues that should show edge filing since that particular mint at that particular time valued round coins over making life easy on 21st century collectors who like to believe that seams and file marks are always bad.  

Those new to the love of fabric might enjoy my page on the subject:

Doug Smith's Fabric Page
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Lloyd Taylor
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« Reply #16 on: March 07, 2013, 06:17:12 pm »

Those new to the love of fabric might enjoy my page on the subject:
https://www.forumancientcoins.com/dougsmith/fabric.html

Very nice. A great introduction and learning resource for those new to the subject. In particular, I lke your statement that ... Remember, however, that most other coins that are less distinctive will show these clues to some degree. Fabric signatures, like handwriting signatures, vary in style, beauty, individuality and the ease with which they are read.

And like handwriting, which is characteristic of a particular individual, the detail of a coin's fabric is specific to a particular mint operation over a limited time frame. When mint operations are studied over a longer a period (typically generations) an evolution in fabric can often be discerned as new workers subtly modify old practices, and invent or import new ones into the minting process. Sometimes we can even see "failed experiments" in new minting technology and/or process in the form of a short lived aberrant fabric in a mint series.... at this point we enter the study of cognitive numismatics, well beyond what the checklist collector considers important in his collecting decisions and priorities.  

For me personally, the study and analysis of the detail of a coin's fabric and how it came to be, makes for a greater interest in numismatics, as it tells us something of what was going on in the manufacture of the coin and is thus an insight into the mint workers, their approach and practices.
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« Reply #17 on: March 08, 2013, 12:33:08 pm »

This is indeed a good thread now, thank you all for spending time here and sharing your observations on this beautiful and important issue.

The incuse mark on coins displays the interesting and beautiful feature that while it is a major and important characteristic of the flan, it is not a product of the earlier stage of the flan's preparation, but it starts existing just from the very moment of the coin's strike, completing and defining what we call fabric at the moment of the birth of a coin! The incuse mark is a major and a very important characteristic of ancient coinage from its dawn, it is directly ralated with what we call flan, it characterizes the appearance, the structure and the feel of coins to the bone, and I think we should refer to it.

Numiswiki's entry on the term 'incuse': Webster's 1913 dictionary defines "incuse" as "Cut or stamped in, or hollowed out by engraving."  The earliest coins did not have a reverse design, but instead had only an incuse mark left by the punch which was struck to force the metal into the obverse die.  Not long after these first coins, a reverse design was engraved into the punch.  Those initial reverse designs, and for several centuries in some places, were struck on the reverse of the coin within the incuse (usually square) left by the punch.

Fifth and fourth centuries BC reverse dies were often square shaped (look at the reverse die of an Athenian Tetradrachm found in Egypt in 1904, pic1. below).
It was the hammer blow of the square shaped die into the flan which had as a result for the flan to acquire its deep incuse square.
The incuse on these issues was part of what we call fabric, a major characteristic of it.
A wide variety of Greek Archaic and Classical types from all over the Greek world bear incuse marked reverses.

The appearance of traces of the incuse on coins of certain types can become an important stylistic factor and helps us not only to decide on the authenticity of the coin, but also with the dating. A good example is the Classical and the massively produced emissions of later Classical Athenian Owl tetradrachms. A general, good "rule" to remember is that on earlier Classical issues, the incuse is more visible, discernible and inside-flan (pic. 2 below). As time passed by and through successive issues, we observe the engraving of the reverse types on a larger scale, the square shaped dies becoming wider; the result was that sometimes the incuse marks are discernible on coins, almost off-flan; this is more evident on the tighter and often misshaped flans of these later issues (pic.3 below).
This -among others- is a good stylistic point to consider when we compare the massively produced Classical owls with each other.

The absence of the incuse in cases when it should be there or its unnatural, fake-ish look and feel, rings a serious alarm bell concerning the coin's authenticity.

For the friends here who read Greek and would like to learn more about the reverse die of the Athenian Tetradrachm, there is Svoronos's detailed article here:

"Σφραγίς Αθηναϊκoύ Τετραδράχμου" in Corolla numismatica, numismatic essays in honour of Barclay V. Head, 1906
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« Reply #18 on: March 08, 2013, 12:36:39 pm »

The incuse mark definitely characterizes certain numismatic types and their eras.
Early Rhodian types of late fifth and fourth centuries BC have incuse reverses (pic. 1 below).
To what a great extend the incuse characterized the early coins is evident by the fact that in the second and the first centuries BC, something like an iconical revival,
a coming back of the incuse square took place in the Plinthophoric series of Rhodes (pic. 2 below).
Having the intention of bringing back some of the charm of their old and glorious coins, Rhodians of the second century BC
restored the incuse square on the reverses of the city's new, reformed coins.
However, there is a major difference between the revived incuse and the early, original incuse. The incuse of the new types is very shallow, and in reality, it is more part
of the design rather than being part of the fabric. The role of the incuse is mainly decorative, having the intention of restoring some of the feel of the early, original incuse coins. The reverse dies of the plinthophoric coins were most probably round, (not square) and there was broad empty space ouside the square; the fact that parts of the magistrates names engraved on the dies outside the square produces good evidence in support of this (pic.3 below). The incuse played only a mere decorative role, being part of the design rather than a result of the minting process. The fashion spread quickly in south-west Asia Minor, and was adopted by the Lycian League and Stratonikeia among others.
Looks like ancient people had their own moments when they looked back with nostalgia, bringing into fashion motives from their past..
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« Reply #19 on: May 27, 2013, 09:55:59 pm »

Fascinating discussion, particularly of the "al marco" weight control mechanism. I assume the gouged slivers from heavy-looking samples were recycled into a subsequent batch of flans? Was any adjustment performed to a set of flans that were too light in toto?

Aha, I located a paper by Clive Stannard on possibly similar adjustments performed on Athenian coinage, which refers to his original study:

Weight adjustment al marco in Antiquity, and the Athenian decadrachm

Quoting Stannard:

Quote
A block of flans is cast at an average weight slightly heavier than the target. They follow a normal distribution, where the mean and mode coincide.

In 1993 I showed that many Roman Republican denarii issues between 123 and 49/48 BC were adjusted al marco; this was possible because of the visible traces of the technique used to adjust the flans before striking, by gouging slivers of metal off the surface with a scorper. This produces characteristic undercut lunate judder marks, belly-forward across the cut. The metal of the judders folds over, and the judder is usually visible, even when the cut itself has been quite obliterated.

Does this recent purchase of mine, a beautiful denarius of P. Plautius Hypsaeus, which features what appears to be a pre-strike gouge on the reverse, exhibit an "al marco" adjustment? It weighs ~3.65g; presumably it would've originally appeared to weigh > 3.79g, and I suppose there may have been significant loss of mass due to wear since creation. I'm curious as to the origin of the small flaw by Leucono's (or Amphitrite's?) earring too.

Regards,
Derek
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« Reply #20 on: May 27, 2013, 11:59:42 pm »

Nice coin!

I don't think this is a Stannard gouge but rather a flan flaw that caused a piece of metal to break off during manufacture, possibly caused by impurities and a gas bubble. The edges are too sharp and jagged. It seems to have been struck-over so it looks like a manufacturing flaw rather than a result of usage or wear. Stannard gouges are always like ice-cream scoop depression, smooth, rounded.

The very definition of al marco means of course that light coins were as often scooped as heavy ones. They only weighed batches, never single coins. So you could get an underweight coin being made even more underweight! But the entire batch would start heavy e.g. weighing about 4 grams average, hence even the underweight coins in the batch would on average be slightly heavier. How did they make the slightly heavier batches? Probably by eye and experience. One batch of 100 coins might weigh 395 grams, the next 403 grams the next 391 grams etc. All that mattered is it weigh at least the official norm of 389 grams. Then they scoop coins until the batches get to 3.89 grams average. Of course the scooped out silver gets thrown back in the pot. The mint slaves didn't get to keep a few percent of the annual worldwide budget for themselves!
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« Reply #21 on: May 28, 2013, 12:28:34 am »

I've no idea about what they'd do with batches that were too light Perhaps they took 10 random blanks out and added 10 new flans, mixed them about and checked again. Richard Witschonke, in a a recent article in the Belgian review, suggests that most forms of mint control (including die control marks) involved quantities of silver moving in batches through the mint. So 38900 grams in bullion in to a workshop at 8am, 10000 coins in counted bags weighing 38900 grams out at 6pm. Both overall weight as well as number of coins counted. The al-marco adjustment would have been a useful tool to make sure it all worked out. Die control marks (marking dies used for specific batches or in specific workshop areas) would have been another tool.
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« Reply #22 on: July 27, 2013, 07:47:01 pm »

Andrew: very interesting, would that be the "Belgian review of numismatics"? I'll have to look for that.

On a related note, and possibly a naive question: were die control marks invariably part of the standard obverse/reverse dies, or was there cases where a second "afterstrike" was used to inscribe the control mark, if such a thing is possible without affecting the original design?

An acquaintance of mine described a similar practice on early American coins (presumably a rediscovery/convergent evolution, rather than a continuation of a known ancient practice!). I quote from
[BROKEN LINK REMOVED BY ADMIN]

Quote
Adjustment marks, also called weight adjustment marks, are file marks on the surface or edges of silver and gold coins minted prior to about 1840. Adjustment marks are most frequently encountered on U.S. silver coins from 1821 and earlier. The reason these file marks were made on the coins was to ensure that the coin was of exactly the proper weight.

Prior to the early ninteenth century, the mint lacked the technology to create coin planchets of the exact specified weights, even though the law demanded that silver and gold coins be of precisely correct weight. The weight of the coin was especially critical at a time when the coin circulated at bullion value, rather than token value. Because the mint didn't have the technological capability to create coin planchets of exact weights, it would try to err on the side of too much, rather than too little weight. If the planchet was too light, there was no way to repair it, so it had to be melted down and recast.

However, if the coin planchet was too heavy, it could easily be fixed by using a metal file to file off bits of the coin metal until the correct weight was achieved. This filing effort left file marks and gouges on the surfaces of the planchets.

Though the page implies that the mint workers tried for an exact adjustment, rather than an accurate average weight or a large batch, so presumably this was far more labour intensive.

Also, to all flan-fans: what do you make of the curious phenomenon at ~3 o'clock on the obverse of my denarius of Thorius Balbus below, where the metal appears appears to have been "folded in" atop the flan? (The edge flaw is distinctly elevated/higher-relief). The coin weighs ~3.79g, and has a die axis of 0. It does not seem to fit the al-marco adjustment description of an "ice-cream scoop"-like "judder", but Stannard does say "The metal of the judders folds over". Presumably a not-particularly-unusual flan flaw, but seemed worth a mention here. (Pic can be clicked for higher resolution).

Regards,
Derek
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« Reply #23 on: July 28, 2013, 04:34:46 am »

Andrew: very interesting, would that be the "Belgian review of numismatics"?

Yes. Online until 2008 but this is a more recent paper.

Revue belge de Numismatique et de Sigillographie

On a related note, and possibly a naive question: were die control marks invariably part of the standard obverse/reverse dies

Yes

or was there cases where a second "afterstrike" was used to inscribe the control mark, if such a thing is possible without affecting the original design?

No

An acquaintance of mine described a similar practice on early American coins (presumably a rediscovery/convergent evolution, rather than a continuation of a known ancient practice!). I quote from
http://coins.about.com/od/coingrading/f/adjustment_mark.htm

Though the page implies that the mint workers tried for an exact adjustment, rather than an accurate average weight or a large batch, so presumably this was far more labour intensive.

This is called "al-peso" adjustment (done for individual blanks) rather than "al-marco" (at a batch level). Indeed it would be a lot more labour intensive. The Romans adjusted gold (but not silver) al peso.

Also, to all flan-fans: what do you make of the curious phenomenon at ~3 o'clock on the obverse of my denarius of Thorius Balbus below, where the metal appears appears to have been "folded in" atop the flan? (The edge flaw is distinctly elevated/higher-relief). The coin weighs ~3.79g, and has a die axis of 0. It does not seem to fit the al-marco adjustment description of an "ice-cream scoop"-like "judder", but Stannard does say "The metal of the judders folds over". Presumably a not-particularly-unusual flan flaw, but seemed worth a mention here.

Yes it is interesting. I would presume that this was a loose sprue which formed at the tail of a blob of metal for the blank, the sprue may have stuck out of the flan and then as a result got struck into the coin. See for example the thin edge sprue of this denarius from my collection - had it been positioned differently it might have been folded over and struck into the coin in the same manner as your coin. I'm almost certain that your instance was an accident. in Republican times the mint workers never paid attention to individual flans so I doubt anyone would have deliberately folded it over before striking. It just protruded in a manner that it was struck-in to the coin.

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DiggingNorway
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« Reply #24 on: January 11, 2014, 05:17:19 pm »

Hi

Since this thread is placed under the "newbie" section, I'd like to share this video, as I, who has just started collating ancient coins, found it interesting.
Greek Coin Production - YouTube Video
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