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Keramický zpravodaj 27 (2) (2011)
section is evidently of natural origin. Another possibility is
the presence of gypsum or palygorskites in the samples
(see the following chapter). It follows from the distribution
of the kinds of clay minerals along the Nile River (Fig. 6)
that palygorskites appear at the upper Nile River. Its pre-
sence in limestone is justified.
The petrographic study of the polished sections (Fig. 9 a,
b) shows that the sample is a fine grained limestone with
lower content of clay matter with well retained - in some
places recrystalised - fossils, which can be found in the
binder. We can also see another clastic material, predomi-
nantly quartz or limonitised grains of pyrite. In reflected
light, one can see the presence of gypsum or anhydrite
near organic substance (probably linked to the contact
with a hyper saline environment).
CONCLUSION
The results obtained in the search and experimental proce-
dures prove that artificial (man-made) materials were pro-
bably not used in the construction of the Khufu’s Pyramid,
but rather that, this structure was built “classically” – i.e.
limestone was quarried in its final size and weight, as we
can see today.
Though my calculations admit that, as far as labour force
is concerned, the method according to Davidovits would
be more advantageous and physically less intensive,
however, a more detailed study of components necessary
Fig. 9a
parallel nicol prisms, enlarged 100x
Fig. 9b
crossed nicol prisms, enlarged 100x
for the manufacture of agglomerated stone has shown
that the idea of the manufacture of artificial limestone
is probably erroneous.
It can be seen from the calculations presented in the previ-
ous chapter, that the manufacture of ash-lime from cere-
als is impossible due to natural conditions. Production of
ash-lime from wood ash would also be impossible due to
a lack of wood in the region in question. And in addition
to this, in case of wood was to have been used for form-
work and for the construction of houses for local inhabi-
tants, the forestation of Ancient Egypt probably would not
be able to satisfy these needs.
Another important component in the manufacture of
geopolymeric blocks was natron. Nevertheless, Davidovits
in his calculations only considers Na
2
CO
3
, but natron has
always occurred in Egypt as a group of several salts. The
manufacture of refined Na
2
CO
3
would have required
a process so complicated, it would not have been realistic
at the time of pyramid construction.
Kaolinite is described in Davidovits’ work as a reactive
component of clay. In the studied samples, its content is
lower than 10 %. It is evident, from experimental works
that its transformation into a binder (hydroxysodalite)
requires its high content in clay, but particularly high con-
centrations of NaOH (~10M). Due to its relatively low solu-
bility, natron could not have provided such high concent-
rations of Na
+
. The Nile River mud could not have been
used as a source of the geopolymeric binder. The clay
reactivity would probably be increased after firing it to
metakaolin at 700 °C but its quantity would still be low,
and even in the alkaline environment of poorly dissolved
natron, it could not be transformed into the geopolymeric
binder.
On the basis of the petrographic study of the sample of
limestone from the casing of the pyramid of Teti, Davido-
vits points out the presence of hair. This argument is then
presented in his all lectures, and he refers to it in many of
his other publications, as the most important argument of
the chemical activation of geopolymeric components by
people. Distinguishing human hair from other mineral fila-
ments in the passing-through light is simple, and it is surp-
rising that it was not carried out in the framework of the
original publication. The study of this so-called “hair”
phenomenon has shown that it need not be a genuine
hair, i.e. an organic fibre, but gypsum or palygorskite com-
ponents (looking like hair) can be included in limestone.
These minerals were detected in X-ray diffraction patterns
obtained after acid leaching of the sample of limestone
from the pyramid casing of Khufu’s Pyramid. The study of
polished sections of the same material confirmed that this
may also be possible cross sections of fossil residues.
The study of samples by X-ray diffraction analysis confirms
that the samples really are natural. Otherwise, distinct
amorphous bands characteristic for geopolymers would
be present in the spectra of insoluble limestone residues.
Nevertheless, no bands like this were identified in the
samples.
With regard to the fact that I do not have the same sam-
ples studied by Professor Davidovits, but other borrowed
samples, there may emerge some speculation about a dif-
ferent interpretation of results. Despite this, my work
documents that a simple possibility to distinguish geopoly-
meric limestone from the natural one exists on the basis
of X-ray analysis of the insoluble residues after their acid
leaching.
The authors are also gratefull to financial support VZ MSM
604 613 7302.