YOU ARE HERE:>>Collectors Resources>>Scientific investigations>>XRF analysis page 2.

 

Generally: for all eight tested

 

Iron: all

Calcium :all

Copper:. In all except fake 3

Lead: only in fake 8

Potassium: only in fake 8

Manganese: In fake 2 and in the genuine 19th dynasty and genuine  4

Strontium: only in fakes 2  and 3 but not in fake 8 and in no genuine one

Vanadium: only in fake 2

Barium: only in fake 2.

 

 

 

  • One does not know what analytical algorithm is applied to the to  extract a profile of either genuine or false.

  • One does not know whether and to what extent the algorithm takes into account absolute values or proportional  values.

 

However looking at these findings it is clear:

 

  • The three definite  fakes are all made from very different compositions.      Each is different from the other and also different from the  known genuine ones. However only one fake (2) was "picked up " by this methods using this database.
  •  After all,  the variable  amounts of lead, strontium, vanadium , barium and potassium which appear from these figures to be found only in fakes were, from these results, not confirmatory either way using this database.
  • The following information is  taken from the detailed compilation  and analyses of XRF findings  in faience glazes in  Ancient Egyptian faience: An analytical survey of Egyptian faience from Predynastic to Roman times by Kaczmarczyk  and  Hedges

 

 



Calcium:

Mean value: 4.5

 

Calcium  will be found in all faience the glazes.

It comes from the lime used  to make up the mixture.

 

These  figures resulted in a correct determination of false  with 2.3% (number 2) but failed to spot the fakes numbers 3 and 8 with 16.4% and 0.6% respectively.

 

So calcium cannot be part of this database's algorithm.

 

Copper:

 

Mean  value: 0.98

 

Copper was deliberately added to create blue and green glazes.

 



.

These figures resulted in a correct determination of false  with  1.2% (number 2) but failed to spot the fakes 3 and 8 with 0% and 1% respectively.

 

.           So copper cannot be part of this database's algorithm

 

 Iron:

 

Widely found in Egyptian  sands and  some will derive from the plant ash used in much faience mixture.

 

Mean  value: 0.38

 

Probably never added deliberated but will be often found in faience glazes up to 1%.

 

Iron was detected in  both the correctly determined  fake and in the two other define fakes "missed".

 

.           So iron  cannot be part of this database's algorithm

 

Tin:

 

Very little tin is found in faience before the 18th dynasty.

Thereafter significant amounts are found; probably added to create a glossier glazes  with more depth of colour.

  



.

Tin was only detected  in two samples here , one definitely  fake , (number 8) and one possibly genuine, (number 5) but both determined as genuine by these results.

The sample correctly  determined as fake  showed no tin, but then so did  the definite fake  number 3 show no tin, but was determined to be genuine.

 

.      So tin  cannot be part of this database's algorithm.

 

Manganese:

Egyptian sands have traces of manganese of around 0.1%

Manganese was deliberately added in rather varying amounts to create various colours in the glaze.

 



This element was found at 0.1% in the fake , number 2 correctly identified as fake.

However it was not found in the other definite fake, number 8, not so  identified and was found in the genuine sample , number 4,

 

.       So manganese cannot be part of this database's algorithm.

 

 

Cobalt.

 

Cobalt is found in trace amount in faience of all periods.

 

It was added deliberately to create blue, violet and indigo colours but disappeared from use after the New Kingdom and reappeared in the Late Period.

 



Cobalt was not detected in any sample here.

 

We cannot say whether  cobalt is part of this database's algorithm.

 

Lead:

The lead content in faience glazes is a complex matter.

Although Jean-Jacques Fiechter says of fake ushabtis in his interesting book, "Egyptian Fakes" on page 193, "...the presence of lead in the paste provides irrefutable proof  of modern manufacture" (no references given) , this is actually not quite accurate.

See Kaczmarczyk and Hedge's tables below:

 




Yellow glazes:

Lead is suddenly found in yellow glazes in the 18th dynasty ( but not before) and then again in the Ptolemaic Period.

It is also found  but in rather smaller amount in the late New Kingdom (19th and 20th dynasties) and the again  in smaller amount in the 26th dynasty to the end of the Late Period, with another sudden peak occurring in the Ptolemaic.

The lead was from the yellow pigment lead antimonite.

Green and blue glazes:

Concentrations of lead in excess of 0.5% are very uncommonly found in green and to a lesser concentration in blue glazes before the sudden peak (and then equally sudden decline) in the Amarna Period and fewer than 10% of either these blue or green glazes have levels above 0.2% unless accompanied by significant amounts of tin and or antimony. Furthermore, both the 18th dynasty and Ptolemaic peaks of lead are found preponderantly with antimony concentration levels above a concentration of 0.2%

Any lead in the glazes was from the use of bronze scrap, which was the source of lead for these glazes. It was of course used deliberately and lead is never found in samples which are very low in antimony.

 

Lead was here detected only in fake number 8 at 2.7% and 1.4% , front and back respectively

This sample was determined as genuine.

 

.            Lead cannot be part of this database's algorithm.

 

Zinc 

Zinc is found in Egyptian pigments only very late.

From the 18th dynasty lead was often added deliberately to specifically yield the yellow lead antimonite and copper- lead green.

Such glazes will also contain  high percentages of zinc oxide but similar glazes of the Late Period and Ptolemaic period are relatively zinc free.

 



Zinc was found in the fake  correctly determined such, number 2,  (4.9%) .

It was  also detected at 0.1% in number 8, the fake  determined as genuine.

High levels  of zinc might be  part of this database's algorithm.

However it would then incorrectly determine as fake post 18th dynasty samples  containing yellow lead antimonite and copper-lead green as these will also contain some zinc

 

Strontium:

 Strontium as an impurity in Egyptian faience is rarely seen and never above 0.05%

 Strontium was detected at 0.1% in the fake number 2 correctly so determined but was also found in the fake number 3 at   0.1% which was  said to be genuine.

        .            Low levels  of strontium cannot be  part of this database's algorithm.

 



Chromium:

This element is found in Egyptian faience rather rarely and only at levels of around 0.06%.

 

Chromium was detected here only in fake number 8  at 0.1%which by these determinations was  said to be genuine.

 

.      Low levels  of chromium  cannot be part of this database's algorithm.

 

Barium and vanadium:

We have next to no data about vanadium in Egyptian sands or faience

Though Egyptian glass

Barium is found  in trace amounts in Egyptian faience but only at levels of about  0.1%

Vanadium  and barium was only here detected in the fake number 2, correctly identified as fake.

 

     Barium and vanadium might be part of this databases algorithm.

 

CONCLUSIONS>>>>>>>>