Is it just the thinness and more exquisite turns of porcelain that make it different from pottery and stoneware....or is there some intrinsic difference between the two?

Is there some kind of clay that is never used in pottery, for instance, that is always used in porcelain?

Pottery feels heavier. Is it just because it is thicker?

And the glaze feels generally smoother on porcelain, but not necessarily so. I have some very smooth-feeling coffee mugs that aren't porcelain...but I honestly cannot say why they aren't other than they're simply heavier than our porcelain teacups.

of troy, you usually know about these types of questions. If you're around, could you (or anyone else) explain the basic differences between pottery and porcelain.

Thanks.

And: Is there a gray area where one is difficult to distinguish from the other (porcelain from pottery)?

Porcelin is a different clay that bakes much whiter and, I think, more translucent. It is stronger which lets you make thinner pieces. Bone china actually does have bone in it.

Zed's gave as much as i know, porcelain (this word came up in the distant past.. it has an interesting etemology, as i recall) is stronger, lighter, and frequently translucent, other pottery, (stoneware, iron stone, terracotta) is heavier, and more fragile (yes, if you use your Lennox china as your every day, it will hold up better than the cheaper kind!)

i vaguely recall that porcelains use those interesting clays we discused last year, the Kaolins (kaolin is word that refers to several different clay compounds) some are used medicinally, (as in kaopectate)-but i could be wrong about that.

porcelains were first perfected in china.

While in Texas last week, I broke a lobe off a crown on one of my molars. My dentist squeezed me in between appointments today and said we will have to remove the old crown and replace it with a new one. (Insert dollar-shock emoticon here.) He kindly ground down the part of the crown remaining which was cutting my tongue every time that member snaked over to touch the wreckage, which it did frequently, pretty much of its own volition). The dentist referred to the sharp edge as "broken glass." I asked why "glass" and he said that "procelain is a kind of glass." Never heard THAT before.

I think porcelain and glass are made of the same thing: sand.

Now I'm wondering about porcelain sinks & other fixtures...

Dr. Bill found the following information somewhere online. His information includes mention of kaolin that of troy had remembered:

"Requires special clay (kaolin)
a special type of clay either white or grey, to which kaolin (a white firing stiff clay) and white China stone (finely decayed granite, washed and prepared as small white blocks) is added. When fired at temperatures of 1,280°C and over (up to 1,400°C was achieved by the Chinese), the body vitrifies, ie it becomes completely impermeable. Glazes can be applied for the first firing, or the vessel can be decorated with a low-firing glaze and put back into the kiln a second time. "

Now perhaps this clay type called kaolin is a silicate of some sort. That would explain the glass and use of the word 'vitreous.'

Edit: Well, it appears all clays are by definition of silicate composition. The vitreous clays, however, appear to be in a group of their own:

http://www.clays.org.au/mins.htm

When I was down in Cornwall with my family a year or so back we visited a wonderful little harbour to see the sail training ships based there:

http://www.cornish-mining.org.uk/sites/charles.htm

– the port had been developed significantly to serve the china clay industry, which even today is a major source of Cornish employment and wealth. This is kaolin, used in all kinds of applications, but made famous in Wedgwood pottery and similar uses.

http://www.wheal-martyn.com/chinaclayind.htm

Earthenware is typically fired in the kiln at around 1100 degrees C, compared to around 1250 for porcelain. There are lots of variants in practise, too:

http://www.heskethps.co.uk/clay/


There is a wealth of wonderful terminology specific to potting – here’s a sample!

http://www.cromartie.co.uk/glossary.htm

Mike, I suspect you could drum up a theme here!


Hope that’s interesting in various ways :)


~ Joe my-dad-had-two-kilns-in-the-garden thursday

oh,yeah, and the etamology..

porcelain
/porslin/

• noun 1 a white vitrified translucent ceramic. 2 articles made of this.

— ORIGIN Italian porcellana ‘cowrie shell’, hence ‘chinaware’ (from its resemblance to the polished surface of cowrie shells).

but why did the italian call cowrie shells porcellana? porcellana refers to an anataomical part of female pig--something only a sow would have..

makes you reluctant to eat off of porcelian dishes!

>etamology

hey!

I think I've been memed!

I don't get the connection between cowrie shell and china ware. But thanks for the porcellana connection, of troy. I will never look at either cowrie shells or porcelain in quite the same way as once before.

And, mav', those are very good links. The pottery terms 'shivering' and 'crazing' are obviously opposites just based on people-based knowledge...and 'glost' had no definition at all, so it might be a good hogwash term.

Today I've learned enough about stoneware and porcelain to be very dangerous if the discussion comes up soon in the real world. Probably won't--too bad for those who like living dangerously. Thanks, everybody, for your replies.

> I think I've been memed!

Thanks for the memery!


WW, you're (as always) most welcome 8}