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chemical composition of terra sigilatta

updated thu 22 jul 04

 

Wendy Lou Jones on mon 19 jul 04


Can someone tell me, or give me a link to a Web site, which will provide the chemical composition of Terra Sigilatta?

I am involved in a renal (kidney) research project, and this fine clay may have potential medicinal properties.

Any information concerning its chemical composition/molecular structure will be appreciated.

WL Jones




Wendy L. Jones
Royal Knight, Inc
2015 41st Street NW
Suite G33
Rochester, MN 55901
Tel/Fax: (507) 289-8192


Author of: "Healthy Living With Demineralization" and "More Bio-fuel Less Bio-waste" Eat and enjoy like you used to for those with impaired kidneys.







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Ivor and Olive Lewis on tue 20 jul 04


Dear Wendy Lou Jones,
You ask <will provide the chemical composition of Terra Sigilatta?>>
Compositions depend on the origins of the "Mother"clay and the stage
of manufacture.
Since Terra Sigillata is derived from natural clay it will contain a
representative proportion of pure clay mineral which may be of the
Kaolinite or Montmorillonite mineral groups, together with residues of
accessory minerals derived from the original rock source.
Once fired, the material is dehydrated and its minerals decompose to
become new chemicals substances.
I know of one text devoted to the nature of Terra Sigillata. You may
be able to find a copy of a paper by Christopher Selwood, "Terra
Sigillata Slip Coatings". ISBN 0-97186-42-5. Published by the
Department of Ceramic Design, Chisholm Institute of Technology, 900
Dandenong Road, Caulfield East , Victoria, Australia 31145. Chemical
analyses of the clays used in these tests are not reported. but there
is a list of references which might guide you to more detailed
information. You might be able to find out about the composition of
the clays by writing to the suppliers of the clays which were used by
Selwood.
The edition of Hamer's book I possess has no reference to Terra
Sigillata but the latest version of the "Big Ceramic Dictionary" may
have.
As an aside and you may be able respond privately on this. Firstly,
how can Sodium chloride be removed from natural spring water and rain
water. Secondly what is the lowest recommended level of intake of this
compound. In other words, how much can be eliminated from our diet
before there are repercussions and we suffer from a deficiency.
Best regards,
Ivor Lewis.
Redhill,
S. Australia.


.

Vince Pitelka on tue 20 jul 04


> Any information concerning its chemical composition/molecular structure
will be appreciated.

Wendy -
There really isn't much to say about chemical composition. Terra sigillata
can be made from any clay. It involves a process of adding a deflocculant
to a thin clay slip solution in order to get the larger particles to settle
out while the fine particles stay in suspension. The decanted mixture
containing only the fine particles is the terra sigillata. Aside from the
very small percentage (less than 1/2 of 1%) alkaline salts added as a
deflocculant, a terra sigillata is entirely clay, which is kaolinite, an
aluminum silicate, with some impurities included.
Hope this helps -
- Vince

Vince Pitelka
Appalachian Center for Craft, Tennessee Technological University
Smithville TN 37166, 615/597-6801 x111
vpitelka@dtccom.net, wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka/
http://www.tntech.edu/craftcenter/

Logan Oplinger on tue 20 jul 04


On Mon, 19 Jul 2004 18:16:55 -0700, Wendy Lou Jones
wrote:

>Can someone tell me, or give me a link to a Web site, which will provide
the chemical composition of Terra Sigilatta?
>
>I am involved in a renal (kidney) research project, and this fine clay may
have potential medicinal properties.
>
>Any information concerning its chemical composition/molecular structure
will be appreciated.
>
>WL Jones
>
>Wendy L. Jones
>Royal Knight, Inc
>2015 41st Street NW
>Suite G33
>Rochester, MN 55901
>Tel/Fax: (507) 289-8192
>
>
>Author of: "Healthy Living With Demineralization" and "More Bio-fuel =96
Less Bio-waste" Eat and enjoy like you used to =96 for those with impaired
kidneys.

Hello Wendy,

I hope this can be of some help without being too discouraging.

Most "terra sig." is made from an already prepared clay body which in turn
is made up of mined and processed clays from different sources. In
addition, other minerals may be added to adjust the properties of the clay
body. Natural clays will also contain other minerals as well as the clay
minerals.

A few clay minerals are:

Kaolin, montmorillonite, halloysite, etc.

Some of the non-clay minerals that can be in a clay body are metal oxides,
sulfates, carbonates, etc; and other non-clay minerals like silica, mica,
and feldspars.

Any clay body can be used to make terra sig. with varying degrees of
success. It is a process of separating the very smallest particles in the
clay body from the larger particles. Please note that I said particles and
not minerals. Even non-clay minerals will be included in the terra sig.

The following web sites may be of some help with more detailed descriptions
of what clay is and how terra sig. is prepared.

http://mineral.galleries.com/minerals/silicate/clays.htm
http://ceramic-materials.com/cermat/education/107.html

You can also use the Google search engine and a search on the words clay &
minerals.

I hope that Vince Pitelka and others with a more extensive background in
preparing terra sig. will respond.

Logan Oplinger
Another Tropical Island

Russel Fouts on wed 21 jul 04


Logan,

I imagine that the chemical composition of Terra sig would vary greatly
depending on the clay.

The characteristics I think you're looking for might be more related to the
extremely small size of the particles.

One of my classmates gave me a ride home one night after my Japanese class
a few years ago. We got to talking about what we do and realised that we're
sort of in the same field. Both our work involves materials of submicron
size. I work with terra-sig and he was doing research into colloidal
materials, mainly to be used as filters. He said that they were working on
filters using extremely small particles of materials, including clay. They
were making filters the size of a sugar cube that had the filtering
capacity (surface area) of a football field. The smaller the particles, the
smaller openings and the larger the surface.

Since Kidneys are filters, maybe they're looking at terra sig as some form
of replacement filter.

Russel



Russel Fouts
Mes Potes & Mes Pots
Brussels, Belgium
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Snail Scott on wed 21 jul 04


At 05:28 AM 7/20/04 -0400, you wrote:
>>Can someone tell me, or give me a link to a Web site, which will provide
>the chemical composition of Terra Sigilatta?
>I am involved in a renal (kidney) research project, and this fine clay may
have potential medicinal properties...


There's not likely to be one, since terra
sigillata can be made from any clay. Its
composition may not mirror the base clay,
however, since the separation process will
tend to leave out coarser particles, and these
may have more of one mineral than another,
changing the final composition of the sigillata.
The initial analysis of the clay would form a
starting point, but if you really wanted
accuracy, you'd probably have to measure the
final material as well. And don't forget to
consider the specific deflocculant used, if
any. It would be a small amount, but possibly
not irrelevant for medical purposes. (It is
possible to make terra sig without any
deflocculant, but it's a lot less efficient.)

-Snail Scott

karen gringhuis on wed 21 jul 04


Wendy -

Think of terra sigilatta as a PROCESS rather than a
molecular compound. Any given clay can be mixed with
water. (It makes no sense to do this with a clay BODY
which is plain clay mixed with other compounds - you
only want the finest plain CLAY particles.) Then an
agent is added to make the clay and water mixture
separate - much of the water rises to the top, the
heaviest coarsest clay particles settle to the botton
and the layed in between is the very finest clay
particles i.e. terra sigilatta. One siphons the water
off the top, then siphons off the terra sig.

For your purposes, I am guessing that clays used by
artists may well include way too many impurities.
Kaolin, as you probably know, is used in many other
industries starting with cosmetics. It's also a key
ingredient in Kaopectate. You may want to find a food
grade (?) source of kaolin and then work with a
biochemist on the precipitation process - if precip.
is necessary at all. Food grade kaolin may in fact be
already a very fine particle - I really don 't know.

Good luck.

=====
Karen Gringhuis
KG Pottery
Box 607 Alfred NY 14802




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