There is certainly silica in wood that can vitrify. As I am sure youre 
phytolith friends would confirm there are very non-diagmostic wood 
phytoliths in many assemblages.

  The ashmounds of  Neolithic South India which consist of large 
accumulation of burnt cattle dung are sometimes vitirifed to the point 
where the silica in the dung has vitirified forming a 'slaggy' scoriaceous 
mass. Frederick Zeuner worked on this problem in the late 50's and through 
experiemntal work showed  that this indicated high  temperatures, close to 
1100-1200 C. (this if from memeory so would need to check on the precise 
figure) to vitrify the silica. I have sampled a number of these mounds, 
they also contain some wood charcoal but it is almost never preserved much 
in the way of internal anatomy due to vitification, presumably because the 
high fire temperatures.





At 15:04 26/08/2004, you wrote:
>Hello, I have seen that glassy look in charcoal from the "destruction 
>level" at Gordion...the wood is pine, from beams burned in a very hot fire 
>(i.e., hot enough to deform the pottery, too, and some of the wheat and 
>lentils also have a gray look). I wonder ... are there phytoliths in wood 
>(i.e., silica) that might vitrify at high temperature?
>
>Naomi.
>
>On Thursday, August 26, 2004, at 09:54 AM, Owen Davis wrote:
>
>>I find these in westernUSAarcheological samples, too. Here, charcoal for 
>>specialists probably isn’t the answer. But, perhaps they might indicate 
>>burning of charcoal from an earlier fire – repeated use of a hearth. I 
>>have also thought the glassy appearance might result from 
>>high-temperature combustion.
>>
>>
>>
>>Yes, experimentation is the best idea.
>>
>>
>>
>>Owen.
>>
>>
>>
>>-----Original Message-----
>>From: The archaeobotany mailing list 
>>[<mailto:[log in to unmask]>mailto:[log in to unmask]] 
>>  On Behalf OfVan Der Veen, Dr M.
>>Sent: Thursday, August 26, 2004 4:42 AM
>>To: [log in to unmask]
>>Subject: Re: deformed charcoal
>>
>>
>>
>>I have found this in my Egyptian material (Mons Porphyrites and Mons 
>>Claudianus), in press.
>>
>>This is likely to happen when charcoal, rather than wood is used for 
>>fuel, ie material is fired twice (usually specialist use of fuel, in my 
>>case in smithies associated with stone quarries)  Though experimentation 
>>would be good idea to test this idea.
>>
>>
>>
>>Marijke van der Veen
>>
>>-----Original Message-----
>>From: The archaeobotany mailing list 
>>[<mailto:[log in to unmask]>mailto:[log in to unmask]]On 
>>Behalf OfBIAX Consult
>>Sent: 26 August 2004 10:48
>>To: [log in to unmask]
>>Subject: deformed charcoal
>>
>>Dear botanists,
>>
>>
>>
>>I am an archaeologist and am involved in wood and charcoal research in 
>>the Netherlands. Regularly I come upon the phenomenon in charcoal, that 
>>the cell walls of the wood seem to have melted and the cell structure has 
>>disappeared . These charcoal fragments have a metallic shine, are very 
>>hard and difficult to break. It often seems to occur in bark fragments 
>>first. Does any of you recognize this and does anyone have an idea what 
>>causes this or where I can find references to this phenomenon.
>>
>>
>>
>>Thanks a lot and greetings from Pauline van Rijn
>>
>>
>>
>>BIAX Consult
>>Onderzoeksbureau voor Biologische Archeologie en Landschapsreconstructie
>>Hogendijk 134
>>1506 AL Zaandam
>>tel. 075 616 10 10
>>fax: 075 614 99 80
>>E-mail [log in to unmask]
>>
>-------------------------------------
>Naomi F. Miller
>University of Pennsylvania Museum
>MASCA-Museum Applied Science Center for Archaeology
>33rd and Spruce Streets
>Philadelphia, PA 19104
>--------------------------------------
>tel: (215) 898 4075; FAX: (215) 898-0657
>www: <[log in to unmask]" target="_blank">http:[log in to unmask]>[log in to unmask]" target="_blank">http:[log in to unmask]
>
></blockquote></x-html>


Dr. Dorian Q Fuller
Lecturer in Archaeobotany
Institute of Archaeology, University College London
31-34 Gordon Square
London WC1H 0PY

http://www.ucl.ac.uk/archaeology/staff/profiles/fuller/index.htm