Antoinette Badenhorst on mon 16 jun 08
I would like to know if it is available to buy and how it compares with the original product from Asia?
--
Antoinette Badenhorst
www.clayandcanvas.com
www.studiopottery.co.uk
Hank Murrow on mon 16 jun 08
On Jun 16, 2008, at 7:25 AM, Antoinette Badenhorst wrote:
> I would like to know if it is available to buy and how it compares
> with the original product from Asia?
Dear Antoinette;
As far as I know, petuntse is not currently being mined and sold in
the USA. There is a deposit of altered rhyolite near San Diego which
is marketed under the name Plastic Vitrox. this stuff is pertly
weathered rhyolite which is not very plastic, but along with feldspar
and Grolleg kaolin can get you pretty damn close to a Jingdezhen
style porcelain.
The main difference between Jingdezhen porcelains from the Song era
and other porcelains, is that the fluxong alkalies are AT THE
MOLECULAR LEVEL. Sorry for the caps, but this is such an important
point, yet mostly overlooked and not well-understood. Also,
porcelains so constituted have a very low Iron and Titania content,
which helps immeasurably in developing translucency and the blue
color of true celadons.
I mine a petuntse here in Oregon for my own use, and there are other
deposits in the cascade range here.
Cheers, Hank
Lee Love on mon 16 jun 08
On Mon, Jun 16, 2008 at 9:25 AM, Antoinette Badenhorst
wrote:
> I would like to know if it is available to buy and how it compares with the original product from Asia?
Talk to Hank. His friend David Stannard of Fairbanks AK has
prospected natural materials.
We've discussed it on ClayCraft. Here is a post Hank wrote to
ClayArt last year. See below:
Hank Murrow on wed 2 may 07
On May 1, 2007, at 3:06 PM, Russel Fouts wrote:
> >> I can't buy this: . You will
> find that small amounts of ball clay have always been added for
> plasticity and dry strength. <<
>
> Hank should weigh in here.
>
> 'True porcelain' doesn't contain ball clay OR Kaolin.
>
> 'True porcelain' is a rock called Petunse.
Well, here we go again. I make no claim that Southern Chinese
porcelains of the Song dynasty forward are 'true'. The porcelains
made in the north of China, before the southern rocks were
discovered, was based upon feldspars and kaolins, etc, just like
their later European brothers.
To protect the Court supply of porcelain wares from the invading and
troublesome hordes, two potters were sent south to find the materials
to make Court wares in a region thought to be safe from the Mongols.
The 'elder brother' found a porcelainous stone which fired grey, and
whose body when fluxed with Lime resulted in a greenish-grey celadon.
The 'younger brother' found a deposit of weathered rock of volcanic
origins creating a body that fired white, and when fluxed with Lime
made a pale blue celadon. Both were the fabled wares of the
Jingdezhen region.
The only difference between the two porcelains was the iron/titania
content of the darker bodies. Sometimes when volcanic rocks are
weathered by hydrothermal alteration, iron and titania are brought
into the rock along with the hot water and geysering. This is what
happened with the Petuntse of elder brother. The rocks of younger
brother's find were free of iron and titania.
this production went on for several generations, and as they mined
the Petuntse(weathered and altered volcanic rock) deeper and deeper,
the clay content diminished and they had to add Kaolin from another
source to retain enough plasticity to work with it. Today, there is
less than 30% Petuntse in the bodies of Jingdezhen.
David Stannard of Fairbanks AK has discovered deposits all along the
Pacific Coast from Oregon to Alaska, that are based upon rocks of
volcanic origin. His work with these rocks is proving seminal, and
mirrors the work Nigel Wood chronicles in his book, "Chinese Glazes",
and it is studio-based, with the intention of working with the
materials to produce wares every bit as 'true' as the Chinese
predecessors. He deserves a big hand from those potters interested in
Porcelain, as does Nigel with his scholarly work.
The point is......... that Western potters and scholars have skewed
our perception concerning what makes a porcelain 'porcelain'. They
can be made from Kaolins and feldspars, or Petuntse (from wherever it
formed) or can be made of both materials in myriad combinations. The
lovely Song pots made with the non-translucent porcelain bodies are
more porcelain-like to me than many of the so-called porcelains on
the market today.
since I will be staying with David while doing my workshop in
fairbanks, I will query him further on these matters and report back
later. Thanks for the question, Russell.
As Bishop William Warburton (bishop of London from 1727) said to Lord
Sandwich, "Othodoxy is my doxy, heterodoxy is another man's doxy". YMMV.
Cheers, Hank
www.murrow.biz/hank
--
--
Lee Love in Minneapolis
http://mashikopots.blogspot.com/
http://claycraft.blogspot.com/
"We are such stuff as dreams are made on, and our little life is
rounded with a sleep." --PROSPERO Tempest Shakespeare
Antoinette Badenhorst on tue 17 jun 08
Thanks for the information Hank. Maybe there is hopes that somewhere in future America will be able to rely on these deposits for their porcelain. Do you get similar translucency as with the southern ice pots you showed me before?
--
Antoinette Badenhorst
www.clayandcanvas.com
www.studiopottery.co.uk
-------------- Original message ----------------------
From: Hank Murrow
> On Jun 16, 2008, at 7:25 AM, Antoinette Badenhorst wrote:
>
> > I would like to know if it is available to buy and how it compares
> > with the original product from Asia?
>
> Dear Antoinette;
>
> As far as I know, petuntse is not currently being mined and sold in
> the USA. There is a deposit of altered rhyolite near San Diego which
> is marketed under the name Plastic Vitrox. this stuff is pertly
> weathered rhyolite which is not very plastic, but along with feldspar
> and Grolleg kaolin can get you pretty damn close to a Jingdezhen
> style porcelain.
>
> The main difference between Jingdezhen porcelains from the Song era
> and other porcelains, is that the fluxong alkalies are AT THE
> MOLECULAR LEVEL. Sorry for the caps, but this is such an important
> point, yet mostly overlooked and not well-understood. Also,
> porcelains so constituted have a very low Iron and Titania content,
> which helps immeasurably in developing translucency and the blue
> color of true celadons.
>
> I mine a petuntse here in Oregon for my own use, and there are other
> deposits in the cascade range here.
>
> Cheers, Hank
Neon-Cat on tue 17 jun 08
Hank wrote:
"The main difference between Jingdezhen porcelains from the Song era and
other porcelains, is that the fluxong alkalies are AT THE MOLECULAR LEVEL.
Sorry for the caps, but this is such an important point, yet mostly
overlooked and not well-understood. Also, porcelains so constituted have a
very low Iron and Titania content, which helps immeasurably in developing
translucency and the blue color of true celadons."
Hi all!
There's a very nice book put out by the Smithsonian Institution Press
entitled "Pottery in the Making, Ceramic Traditions", edited by Ian
Freestone and David Gaimster, 1997, ISBN 1-56098-797-9. Through a
collaborative effort between archaeological, ethnographic, and scientific
groups along with insightful input from documentarians an entire collection
from the British Museum's collection is analyzed. There are nice chapters on
Ding and other Whitewares of Northern China and a great chapter on Chinese
Porcelain from Jungdezhen. They give clay body and glaze compositions,
detail firing methods, show groovy photos (micrographs, etc.) of clay-glaze
interfaces and clay bodies, discuss how the ceramic materials were mined,
give historical sketches of the eras under discussion, and have nice photos
of pieces from each period discussed. This book is a nice read, a good
reference, and a great way to gain more understanding of clay bodies and
glazes. I got my new copy at a local half off book store for $5.98. I am
continually delighted by the science of the book and the beauty and
durability of the ware presented. Many historical eras are profiled.
Marian
neon-cat.com
Texas
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