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 Replies: 13 / Views: 7,283 |
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Pillar of the Community
United States
564 Posts |
I was just wondering how much lead do ancient coins from Rome/China have?
Diem
*** Moved by Staff to a more appropriate forum. ***
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Moderator
 United States
23731 Posts |
Not a question that can easily be answered without testing a large number of different coin types.
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Moderator
Australia
16849 Posts |
Ancient metal refining techniques were not as efficient and precise as our modern technologies. Lead is a very common background element in coins, be they gold, silver or bronze. I have a collection of scientific research papers which were compiled into a book on numismatic metallurgy, which offers the following insights following chemical analysis of lead in coins:
- Ancient "archaic period" Greek silver coins: lead levels ranging from 0.05% to 3%
- Mediaeval English Northumbrian brass stycas: lead levels ranging from 0.5% to 2%
- Ancient Roman bronze coins, early 1st century: lead levels ranging from zero to 0.4%
- Ancient Roman silver coins, late 1st century: lead levels ranging from 0.2% to 0.9%
- Mediaeval Byzantine base-silver trachy: one analysed, lead reported at 0.99%
- Mediaeval Islamic Samanid double-dirham: one analysed, lead reported at 0.44%
- Mediaeval English Edward III pennies: two analysed, reported lead results 0.85% and 0.96%
- Mediaeval Scottish debased-silver coinages: lead levels ranging from 0.4% to 1.1%
As you can see, levels of lead around 1% are quite common; certain series are known to be much higher in lead. Late-period Romano-Egyptian tetradrachms, for example, are often quite high in lead.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis
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Moderator
United States
34427 Posts |
Very interesting @sap. Could you please share the title and author of your book on numismatic metallurgy?
"If you climb a good tree, you get a push."
-----Ghanaian proverb
"The danger we all now face is distinguishing between what is authentic and what is performed."
-----King Adz
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Moderator
Australia
16849 Posts |
"Metallurgy in Numismatics, Volume 1" edited by D.M. Metcalf and W.A. Oddy, published by the Royal Numismatic Society in 1980. I have no idea if they ever made further volumes.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis
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Moderator
United States
34427 Posts |
Ok super--thanks! I can find all four volumes on the ABE website.
"If you climb a good tree, you get a push."
-----Ghanaian proverb
"The danger we all now face is distinguishing between what is authentic and what is performed."
-----King Adz
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Moderator
United States
23731 Posts |
I didn't know a study was done on so many different types. That is really interesting.
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Pillar of the Community
United States
3443 Posts |
I have read that the practice of recycling bronze coinage from previous regimes lead to the degadation and "embrittlement" of the alloys. Particularly the orichalcum used in the sestertius and dupondius. In recycling of alloy it is recommended that more than half the alloy always be "fresh". By smelting old coinage the process leads to evaporation and loss of the zinc which gives orichalcum its golden color. Additionally the increases in lead content (counter intuitively) leads to the actual embrittlement of the alloys which is why later bronzes often have large fractures. Of the first century bronzes in my collection none have fractures. By late 2nd century and early 3rd century they become the norm. Romans were good metallurgists but some things (like evaporation) were beyond their understanding. Recycling iron weapons was necessary as they were often broken when used. Repeated smelting of iron eventually creates low grade steel as carbon is absorbed from the coal used to fire the furnace. In that case they certainly could not have understood how it was happening but certainly appreciated the improvements in performance. I am sure the better steel blades were highly prized heirlooms. Not too long ago I found this on ebay. A seller in Spain had what looked like some detector finds. Mostly assorted Roman coins and 'stuff'. I bought a nice denarius and spied this oddity. I believe it is an ingot from a small backyard smelting operation. It is lead. 45mm and weighs just over 85 grams.  |
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Valued Member
Spain
108 Posts |
Hi! I am sorry. Now, I see this topic. We can find lead not only as a trace but as an element in bronze alloy (ternary bronze: copper, tin and lead). So is very usual in iberian and roman-hispanic coins. I attach this graphic from a 1995 paper (Juan Manuel Abascal and Pere Pau Ripolles: Composicion metalica de algunas monedas ibericas del Museu d,A lcoi). References are V (Vives) and Vill (Villaronga)  Edited by Veton
06/18/2017 07:38 am
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Valued Member
Spain
108 Posts |
FVRIVS RVFVS, perhaps your ingot is a cap, stopple or similar, (it seems to be screwed in order to fit well in the mouth of some kind of recipient ?).
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New Member
Canada
2 Posts |
@sap Thanks for info. I got recently an antiochos 1 tetradrachm (16.75 gr) and did XRf on it and found it has 99.53% silver, 0.42% gold and 0.05% lead. I know you mentioned that in ancient greek coins lead could be between 0.05% to 0.3% which my coin seems to be on minimum level but I remember I read in some article that investigated fakes vs authentic coins that one way they recognized fake was by the fact that lead content was less than 0.1% and they said this level of purification was not possible by ancient techniques. I appreciate your opinion on this coin.  |
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Pillar of the Community
United Kingdom
2624 Posts |
Wow so much information in one thread... it is one of the marvels of the forum that an obscure question can be asked and all the knowledge in the world seems to spring forth.
As for you coin Arashpour it looks like a beauty to me.
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New Member
Canada
2 Posts |
Thanks @DavidUK if it is authentic then it will be an amazing coin. Only fact that makes me a bit worried is low lead content but this thread shows that some greek coins had 0.05% lead which I would like to know.
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Moderator
Australia
16849 Posts |
I personally would not worry about this coin, given those results; my reasoning being, modern silver alloys have all of the gold stripped out of them. The high gold content makes me think this piece of silver is ancient.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis
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Replies: 13 / Views: 7,283 |
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Posted 05/06/2017 08:13 am
