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Some simple observations on ancient coin flans

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Andrew McCabe:
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!

Andrew McCabe:
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.

Equity:
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.

--- End quote ---

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

Andrew McCabe:

--- Quote from: Equity on July 27, 2013, 09:47:01 pm ---Andrew: very interesting, would that be the "Belgian review of numismatics"?

--- End quote ---

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

Revue| belge| de Numismatique| et de |Sigillographie


--- Quote from: Equity on July 27, 2013, 09:47:01 pm ---On a related note, and possibly a naive question: were die control marks invariably part of the standard obverse/reverse dies

--- End quote ---

Yes


--- Quote from: Equity on July 27, 2013, 09:47:01 pm ---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?

--- End quote ---

No


--- Quote from: Equity on July 27, 2013, 09:47:01 pm ---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.

--- End quote ---

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.


--- Quote from: Equity on July 27, 2013, 09:47:01 pm ---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.

--- End quote ---

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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