I've also noticed that certain taxa (Olea, for example) exhibit
vitrification more frequently than others, perhaps due not only to
fire temperature, but also to structural differences and variation in
silica content. In olive wood, I see vitrified ray cells more
frequently than other kinds of cells. In the Mediterranean, olive is
often used in kilns due to its ability to sustain high temperatures.
There was a parallel discussion on this topic several years ago on the
list, but I don't have the messages archived -- might be worth having
a look at these as well.
On Apr 21, 2009, at 6:51 AM, Niels Bleicher wrote:
> Dear colleagues,
> couldn't it be possible that hardness and texture are also related
> to the water content during burning? So they need not be related to
> temperature alone but also how well the wood was seasoned before. I
> wonder whether there are any published experiments on this and
> especially on the vitrification. Does anybody know?
>> -----Ursprüngliche Nachricht-----
>> Von: "SARPAKI ANASTASIA" <[log in to unmask]>
>> Gesendet: 18.04.09 13:03:57
>> An: [log in to unmask]
>> Betreff: Re: hardness of carbonized wood charcoal
>> Dear Minkoo,
>> This sounds very much like what Christine says...Is it possible
>> that this kiln was used in order to transform wood into charcoal
>> for use as charcoal?? In Greece, they used to make make shift kilns
>> which produced charcoal for selling as such and in this case the
>> charcoal that we find has a very diffirent hardness (much much
>> harder) and texture (it is not brittle in the same way normal
>> charcoal burnt on site is). This wood have been very convenient to
>> use in houses where openings are not too large I suppose as it does
>> not make as much smoke as fresh wood.
>> Just an idea...
>> Christine Hastorf <[log in to unmask]> wrote:
>>> Dear Minkoo,
>>> this sounds like the wood has burnt at a very high temp such that
>>> is is
>>> the cells are melted.
>>> I hope all is well, spring has arrived here!
>>> Minkoo Kim wrote:
>>>> Dear All,
>>>> I am analyzing wood charcoal from ancient ceramic kiln, and have
>>>> noticed that some wood charcoal remains (although they looked
>>>> carbonized) were extremely hard. They were so hard that I could
>>>> even break with sharp razor. When I managed to break them open,
>>>> of them showed shiny sections that looked as if they were
>>>> glazed. I
>>>> suspect this is probably related to the temperature of the kiln for
>>>> which the wood was used as fuel. I would greatly appreciate if
>>>> someone can explain whether kiln chamber temperature is related to
>>>> charcoal condition.
>>> Department of Anthropology
>>> University of California-Berkeley
>>> Berkeley, CA. 94720-3710
> Niels Bleicher
> Burgstrasse 20
> 8037 Zürich
> Tel.: 0041 (0)43 4886045
Dr. Susan E. Allen
Department of Anthropology
University of Cincinnati
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