Classical Numismatics Discussion
  Welcome Guest. Please login or register. 10% Off Store-Wide Sale Until 2 April!!! Explore Our Website And Find Joy In The History, Numismatics, Art, Mythology, And Geography Of Coins!!! Expert Authentication - Accurate Descriptions - Reasonable Prices - Coins From Under $10 To Museum Quality Rarities Welcome Guest. Please login or register. 10% Off Store-Wide Sale Until 2 April!!! Explore Our Website And Find Joy In The History, Numismatics, Art, Mythology, And Geography Of Coins!!! Support Our Efforts To Serve The Classical Numismatics Community - Shop At Forum Ancient Coins

New & Reduced


Author Topic: What metal is used for late empire coins?  (Read 3644 times)

0 Members and 1 Guest are viewing this topic.

Offline Brian L

  • Caesar
  • ****
  • Posts: 620
What metal is used for late empire coins?
« on: August 16, 2009, 08:41:48 pm »
Can someone tell me what metal coins like Fel Temp,Campgates,Votif, etc were made of?
They are always referred to as AE 1,2,3,4,
AE is described as copper,nickel,brass,or bronze.
SO, What were the late empire coins made of?
Were they solid copper,or a mix of metals like brass or bronze
                 Thanks
 
       
Those who stand for nothing,will fall for anything.- Alexander Hamilton
My Gallery:  https://www.forumancientcoins.com/gallery/index.php?cat=21532

Offline commodus

  • Tribunus Plebis Perpetuus
  • Deceased Member
  • Caesar
  • ****
  • Posts: 3291
Re: What metal is used for late empire coins?
« Reply #1 on: August 17, 2009, 12:29:56 pm »
Bronze, alloyed with other base metals in varying proportions.
AE derives from the Latin aes, meaning bronze, but is used for bronze, copper, and brass alloys such as orichalcum, from which sestertii were made.
Billon (a bronze/silver alloy) is also sometimes denoted as AE.
Few, if any, late imperial Roman coins were struck in unalloyed copper. The majority are various bronze alloys.
No ancient coins -- indeed no coins of any nation until the mid 19th century to my knowledge -- were struck in nickel and AE does not refer to this metal.

The numbers (i.e. AE: 1, 2, 3, 4, 5) refer to the size of the coin for later Roman bronze types for which the historic name of the denomination is either unknown or in question.
Eric Brock (1966 - 2011)

Offline quisquam

  • Caesar
  • ****
  • Posts: 509
Re: What metal is used for late empire coins?
« Reply #2 on: August 17, 2009, 01:04:19 pm »
Aes just means ore. All these 4th century coins are of red metal, basically made of copper, some with a probably intended silver content of maybe 1-2%, some without, depending on the denomination (not necessarily the size).

Stefan

Offline wandigeaux (1940 - 2010)

  • Deceased Member
  • Caesar
  • ****
  • Posts: 873
Re: What metal is used for late empire coins?
« Reply #3 on: August 17, 2009, 03:51:31 pm »
Somebody will doubtless elaborate, but there were a few Indo-Greek coins struck in an alloy of nickel (probably of natural origin, perhaps meteoric).  George Spradling
Hwaet!
"The pump don't work 'cuz the Vandals took the handle" - St. Augustine
GET THE HELL OFF MY LAWN!!
(1940 - 2010)

Offline commodus

  • Tribunus Plebis Perpetuus
  • Deceased Member
  • Caesar
  • ****
  • Posts: 3291
Re: What metal is used for late empire coins?
« Reply #4 on: August 17, 2009, 03:53:46 pm »
aes does mean ore and in archaic Latin specifically copper ore. However, by the second century or so BC it had come to mean bronze and throughout the empire it had that specific meaning. All LRBs are copper alloys. Some are billon (with silver admixtures) and many are bronze (with base metal admixtures).
Eric Brock (1966 - 2011)

Offline commodus

  • Tribunus Plebis Perpetuus
  • Deceased Member
  • Caesar
  • ****
  • Posts: 3291
Re: What metal is used for late empire coins?
« Reply #5 on: August 17, 2009, 03:55:22 pm »
Somebody will doubtless elaborate, but there were a few Indo-Greek coins struck in an alloy of nickel (probably of natural origin, perhaps meteoric).  George Spradling

Thanks. Was unaware of this. Nickel is such a hard metal that it was generally impractical for coinage until the advent of steel dies.
Eric Brock (1966 - 2011)

Offline slokind

  • Tribuna Plebis Perpetua
  • Procurator Monetae
  • Caesar
  • *****
  • Posts: 6654
  • Art is an experimental science
    • An Art Historian's Numismatics Studies
Re: What metal is used for late empire coins?
« Reply #6 on: August 17, 2009, 04:44:59 pm »
Late Roman antoniniani and folles, apart from any surface silver, are basically copper.  There is a British Museum study that shows them all (Occasional Paper no. 120, 1997).  Remember that before electricity was understood, and conducted, copper, always common and easy to use, was not so highly valued.  A glance at the charts of all the Gallienus coins they analyzed shows over 80% copper: just impure enough to make them hard enough.
Bronzes (note the plural) vary, according to what casting characteristics, what color, etc., are desired, also according to the available metals for alloying.  So they vary according to use (clamps and dowels, coins, statues, vessels to be plated, partigilt—if I spelled it right—like the Sassanian plates and bows).  So dear old Caley called 'em 'copper alloys' which, metallurgically, is correct.  Easier to call 'em all aes.  Where available,  tin is the usual primary alloy-metal.
Copper should be reasonably pure to be so called; it often has lots of trace elements native to it.
Orichalcum of the best period, in Rome usage, is about 80% copper with about 20% zinc. 
Modern brass comes in two kinds: like church brass, often under 20% zinc and so warmer-colored, and machine brass, often well over 20% zinc, so more lemon-yellow and more brittle, but harder.  Good brass screws are machine brass.
The trace elements should cumulatively be less than 1%.
From Marcus Aurelius onwards, the Rome mint seems to have had a zinc problem; probably its cost, to smelt it from the ore and for transportation (but we don't really know), when the dupondius and sestertius lost their former buying power, made the Rome mint not only melt down worn coins and even scrap but also substitute other metals for the zinc.  Sestertii of the later periods are seldom really orichalcum and really interesting in their varying alloys.
Pat L.

Offline dougsmit

  • Tribunus Plebis Perpetuus
  • Procurator Monetae
  • Caesar
  • *****
  • Posts: 2126
    • Ancient Greek & Roman Coins
Re: What metal is used for late empire coins?
« Reply #7 on: August 18, 2009, 08:58:54 pm »
Late Roman antoniniani and folles, apart from any surface silver, are basically copper.  There is a British Museum study that shows them all (Occasional Paper no. 120, 1997). 
From Marcus Aurelius onwards, the Rome mint seems to have had a zinc problem; probably its cost, to smelt it from the ore and for transportation (but we don't really know), when the dupondius and sestertius lost their former buying power, made the Rome mint not only melt down worn coins and even scrap but also substitute other metals for the zinc.  Sestertii of the later periods are seldom really orichalcum and really interesting in their varying alloys.
Pat L.


If you compare all your Late Roman coins, you may note that there are periods where the metal wears smoother than others.  I always associated this to times when there was no silver in the mix.  It happens in the minors of Diocletian's reform and most coins after about the 370's.  I have not seen this BM paper but the thought process of the day made 4.7% and 1% very big deals even both looked 'basically copper'.   I wonder how much attention was placed on the matter of the content of the alloy other than the silver but suspect it was more dependent on what was available easily than on policy. 

As I understood the situation, ancient brass was (almost?) never produced from metallic zinc but by melting a zinc compound (sulfide, oxide) with the copper (and carbon?).  Ancient objects showing any ability to smelt it from ore are rare and there is no need when it can be done the other way.  Does anyone have references on this?

Offline PeterD

  • Procurator Caesaris
  • Caesar
  • ****
  • Posts: 1483
  • omnium curiositatum explorator
    • Historia
Re: What metal is used for late empire coins?
« Reply #8 on: August 19, 2009, 07:30:14 am »
The BM paper shows that the percentage of impurities (and the required metals) vary enormously for all periods. The highest percentages of impurities are usually lead and tin, although these were sometimes deliberately added to change the appearance of the coin.

There are only a few early bronzes in the BM paper, but a group of dupondii from the time of Augustus show the zinc content varying between 12% and 24%. Most of the paper relates to the late 3rd - early 4th century. Here again plenty of impurities. The silver content, although of course decreasing over time, varies considerably even for the same issues, as does the absolute weight. Looked at from the perspective of copper content, from the time of Claudius II, when silver content was very low, the percentage of copper rarely exceeded 90%. In the Constantinian period there seems to have been quite high levels of tin and lead (although as usual very variable) which might account for the different wear.
Peter, London

Historia: A collection of coins with their historical context https://www.forumancientcoins.com/historia

SPQR

  • Guest
Re: What metal is used for late empire coins?
« Reply #9 on: August 25, 2009, 09:32:14 am »
I've a sneaking suspicion that more than a few coins contain whatever metal happened to be cheapest and closest to the particular mint in question, and the later one goes the worse it gets. We also know that many coins were made from captured booty and distributed during triumphs, or minted up to pay for further campaigning. Who knows what might have gone to the smelter as booty and come out as sestertii?

Offline commodus

  • Tribunus Plebis Perpetuus
  • Deceased Member
  • Caesar
  • ****
  • Posts: 3291
Re: What metal is used for late empire coins?
« Reply #10 on: August 25, 2009, 11:55:05 am »
Well, by the late empire they wouldn't be comming out as sestertii but rather as nummi and folli and maiorini, but that is a very good point.
Earlier in the empire, quality control over the metals used at the mint would have been high.
Eric Brock (1966 - 2011)

Offline PeterD

  • Procurator Caesaris
  • Caesar
  • ****
  • Posts: 1483
  • omnium curiositatum explorator
    • Historia
Re: What metal is used for late empire coins?
« Reply #11 on: August 25, 2009, 02:36:22 pm »
The early bronze coins seem to contain as many impurities as the later ones. Modern numismatists obsess about the composition of ancient coins and use modern techniques to test them. But how could the Romans have known what impurities there were in their metal? More importantly, why would they care? If it looked like copper, it was copper.
Peter, London

Historia: A collection of coins with their historical context https://www.forumancientcoins.com/historia

 

All coins are guaranteed for eternity