Dan

I would concur with Peter but add that antimony is a significant
impurity in some medieval and post-medieval alloys used for large
casting (in particular domestic cooking vessels such as cauldrons). In
this case it seems to be the deliberate use of de-silvered copper
obtained from fahlerz type ores. See

Dungworth, D. & Nicholas, M. 2004. 'Caldarium? An antimony bronze used
for medieval and post-medieval cast domestic vessels'. Historical
Metallurgy 38: 24-34.

For further details, etc

David


Dr David Dungworth
Materials Scientist
English Heritage
Fort Cumberland
Portsmouth
PO4 9LD
Tel:   023 9285 6783
Mob: 07982 304315

-----Original Message-----
From: Arch-Metals Group [mailto:[log in to unmask]] On Behalf Of
Peter Northover
Sent: 22 March 2007 16:20
To: [log in to unmask]
Subject: Re: Information involving trace elements in Bronze Age weapons

Dear Dan,


Antimony appears as an important element in copper and copper alloys on 
a number of horizons in prehistory. In general it seems that 
copper-antimony binary alloys are unusual, at least in my experience; 
the only time I think I have seen antimony as the sole impurity in 
bronze above trace levels was in an alleged grave group from the Warring

States period in China, where in fakes made from an otherwise clean 
leaded bron ze the antimony came in with the lead because scrap battery 
plates or a similar alloy had been used.

In the Nahal Mishmar hoard already cited in this discussion there is 
also aresenic. Cu-As-Sb compositions with percentage levels of antimony 
are quite common in areas ranging from the Irish Chalcolithic to 
prehistoric Bactria, but usually arsenic is the dominant element of the 
two. This is not so in central/Alpine Europe in the Early Bronze Age (Bz

A) where coppers smelted from fahlerz ores have very significant 
antimony contents, up to several percent in Swiss Salez type axes. These

contain some nickel and silver, the nickel I suspect aiding the 
ductility of the alloy (not necessarily a bronze as tin can be low or 
absent).

In the Middle Bronze Age in much of northern and western Europe there is

a switch back to pyritic ores but with the beginning of the late Bronze 
Age (Ha A2 in central European chronology, LBA 1 in Britain, BF II in 
France and Montelius IV in Scandinavia) fahlerz is again very important.

In central Switzerland in about Ha B2 (see publication of Zug-Sumpf) 
there was for some reason a shortage of tin and antimony-rich copper was

substituted, with an inverse correlation between tin and antimony, and 
antimony up to 8%. This metal was used for a variety of object types.

In prehistory the last occurrences of copper with high antimony contents

for several hundred years are in ingot material of the beginning of the 
Iron Age in eastern Switzerland, the Ticino and Slovenia. In the last 
named some very complex Cu-As-Sb-Ni compositions are found, and have 
been published extensively. There are later occurences, for example in 
medieval Britain, but these are for cast vessels of low quality.

In Luristan when bronze was established antimony seems to be a modest 
impurity.

Peter
-- 
Dr Peter Northover,
Materials Science-Based Archaeology Group,
Department of Materials, University of Oxford
Tel +44 (0)1865 283721; Fax +44 (0)1865 841943 Mobile +44 (0)7785 501745
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