<HTML>Well, this shows what I have told you for some time now: Davidovits have produced something that LOOKS like fayence, but IS NO fayence. Fayence, to repeat myself for the millionth time, consists of quarz grains bound together by GLASS and not by some zeolite.
For the proposed low-temperature-process I quote from Nicholson (Egyptian Fayence & Glass, p. 42) about the stages of glass making (which are up to the fritting nearly identical with fayence):
"Silicia was obtained from sand, <b>crushed flint</b> or quartz."
Well flint is one of the hydro-silicas you namely quoted. So if they used it for glass - hey, they could melt it with a candle. But let's go on:
"The silica is the network former for glass but, in order to melt it at sufficiently low temperatures, ancient workers found it necessary to add a network modifier in the form of alkali. This served as flux in the process."
Well, up to here it goes conform with Davidovits.
"Alkalis were added in the form of plant ashes ... or as natron. Ancient texts ... do not mention the addition of lime and it must be supposed that this was generally present as an impurity in sand. ...
Alkali consists of carbonates which react with the silica to make sodium silicate and carbon dioxide.
[...]
The first stage, known as fritting, involved the heating together of the raw materials at a temperature between 700 and 50°C until they formed a mass resembling partly melted sugar. ... if 850°C is exceeded the mixture ... begins to melt."
So THAT is the needed temperature when YOUR OWN reciepe is used. 850°C to melt such a material together. Not 1300 °C
Back to fayence: Unfortunately some body materials found have so less Al-content that it is not measureable, and half of the samples analyzed by Lucas have contents between 0,1 and 0,6% - a little low for such a necessary material, isn't it?
My final words are a quote from Nicholson (Egyptian Fayence & Glass, p. 16): "Faience, frits and glass are part of a continuum of materials based on silica plus varying amounts of alkali, lime and copper, though they are distinct in terms of their composition since it would not be possible to turn fayence into frit or frit into glass simply py prolongig heating...
The addition of further alkali would be necessary.
...
It is not unlikely, that faience, frit and glass were all made in close proximity, possibly in the same workshop complex..."
It is ONE family.
Faience = Frit with less alkali and fired shorter, not onto its all melted but until you have a stable glass matrix and an opaque body
frit = glass with less Alkali and fired shorter, too, to get only a translucent piece without remining opaque body
glass = transparent, yet colored alkali rich frit.
Unless Davidovits can produce faience with glass matrix, it's finito for the theory.
FD</HTML>
