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Copper Content of Lampsacus Electrum types

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glebe:
Two of the odder coins listed in Gitler et al's XRF analysis of the early electrum coins are the two late 5th cent. types from Lampsacus (coins 44 & 45).

These types are in the style of the contemporary Kyzikene types, but the alloy compositions are rather different.

The gold contents of the Lampsacus coins are 58 and 59%, which matches the Kyzikene types, but whereas the copper percentages at Kyzikus are generally quite high, in the range of 3-5% or more, the figures for Lampsacus are 0.30 and 0.31%.

Now these figures are amazingly low, much lower than for pretty well all of the other coins listed (particularly the later types).

Except of course for our old friends the two plain types of Samos (coins 1 and 36), for which the copper figures are 0.61 and 0.35%.

What does this mean, I hear you cry.

Ross G.

glebe:
Actually I tell a lie. Among the 91 Kyzicene examples there are a small number with ultra-low copper levels, namely coins 85 (0.60%), 56 (0.53%) and particularly 97 (0.19%) and 98 (0.13%). And a few more with copper levels around 1%.

Otherwise the figure is generally something like 3% or more.

Did they forget to add the extra copper?

Ross G.

Oops - should be coins 85, 86, 96 & 97.

SC:
Supply chain problems 25 centuries ago....

SC

PtolemAE:

--- Quote from: glebe on October 17, 2021, 04:11:20 am ---Actually I tell a lie. Among the 91 Kyzicene examples there are a small number with ultra-low copper levels, namely coins 85 (0.60%), 56 (0.53%) and particularly 97 (0.19%) and 98 (0.13%). And a few more with copper levels around 1%.

Otherwise the figure is generally something like 3% or more.

Did they forget to add the extra copper?

Ross G.

--- End quote ---

Possible the difference is (trace) copper content of the silver used to dilute the gold, i.e. maybe no use of copper as a separate alloy component and no knowledge by makers of how much copper was even present. Might be helpful to know the full elemental composition from the two locations to see if content of other elements like lead, zinc, antimony, etc. correspond to differences in copper content. Could be less to it than meets the eye.

PtolemAE

glebe:

--- Quote from: PtolemAE on October 18, 2021, 12:45:29 pm ---
--- Quote from: glebe on October 17, 2021, 04:11:20 am ---Actually I tell a lie. Among the 91 Kyzicene examples there are a small number with ultra-low copper levels, namely coins 85 (0.60%), 56 (0.53%) and particularly 97 (0.19%) and 98 (0.13%). And a few more with copper levels around 1%.

Otherwise the figure is generally something like 3% or more.

Did they forget to add the extra copper?

Ross G.

--- End quote ---

Possible the difference is (trace) copper content of the silver used to dilute the gold, i.e. maybe no use of copper as a separate alloy component and no knowledge by makers of how much copper was even present. Might be helpful to know the full elemental composition from the two locations to see if content of other elements like lead, zinc, antimony, etc. correspond to differences in copper content. Could be less to it than meets the eye.

PtolemAE

--- End quote ---

The XRF figures are available here:

https://www.researchgate.net/profile/Haim-Gitler/publication/338676783_XRF_Analysis_of_Several_Groups_of_Electrum_Coins/links/611ce6640c2bfa282a514671/XRF-Analysis-of-Several-Groups-of-Electrum-Coins.pdf

The figures for the trace elements for the Kyzicene coins 96 & 97 (not 97 & 98 - sorry) other than Cu are quite normal.

Also there are four other examples of this particular series (von Fritze 121) in the tables which have the usual 3% or so of Cu.

So I'm wondering whether the super low Cu figures for coins 96 & 97 might be typos. Similarly 85 & 86 (56) perhaps.

Ross G.

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