Mark Hewitt Pottery > Pottery Blog > THE MATERIAL SOUTH – Chandler Rock

South Carolina was home to an important regional pottery tradition in the nineteenth century, partly because of the clays and glaze materials found there. I’ve long admired the work of one of those potters, Thomas Chandler, 1810-1854, who made handsome two handled jugs and sturdy crocks, often decorated with lively slip-trailed decorations. Part of their beauty lies in the nature of the specific materials he used.

This story is about my quest to get and refine one of his glaze materials.

My quest is not for the purposes of historic reproduction. It’s because his glazes are so complicated, mysterious, and beautiful, and I can’t help but want to make the prettiest pots I can with it. Chandler showed me something, and I want to follow his lead and elaborate on it, and do it my way.

It’s like hearing a bittersweet lament that carries the weight of the world and you can’t get it out of your head, a siren song that lures me to the rock. I know what old Northern Thai celadons and Sung Dynasty Chinese celadons look like, and how they relate to Chandler’s glazes, and can’t settle for using generic glaze materials to make something that Japanese potter, Shoji Hamada, once said, “looks good, but isn’t.

Here are some of the wonderful pots made by Thomas Chandler (1810-1854)

Chandler jug

Chandler Crock

Chandler Crock

Chandler detail

Chandler Crock

Chandler Bowl

This quest began in earnest a couple of years ago when my old friend Phil Wingard, a retired schoolteacher, historian, and antique dealer, brought me some rock he’d found while sleuthing close to the Chandler kiln site at Kirksey’s Crossroads, near Edgefield, SC. He noticed an outcrop with peculiar chunks out of it, and had a hunch that it might be the rock out of which Chandler made his glazes.

The rock appears to be a type of feldspar, which is a major component of stoneware glazes. So, my former apprentice, Hamish Jackson, and I set about making it into a powder to use as an ingredient in a series of test glazes.

Turning rock into a glaze
First, we calcined (fired) the rock in my gas kiln up to 1700 Fahrenheit which loosens the bonds that hold together the felspar crystals in the rock. Then we crushed it by hand, tamping it into pea gravel sizes or smaller using a heavy steel tamper. Next, we put the gravel and some water into my ball mill and ground the gravel for eight hours until it became a very fine powder.

Hamish then created a triaxial blend of three different martials – Chandler Rock, limestone, and a ball clay – in this case, a clay from Tennessee called XX Saggar.  

The calcium in limestone, calcium carbonate, is used as a flux to help felspar melt at a lower temperature, and alumina in ball clay is used to prevent the melting glaze from running off the pot if it gets too hot.

Hamish also made test tiles to dip into small quantities of all the different combinations of those three materials. We then fired the tests to cone 12 (2375F) in my gas kiln and when we unloaded it, we had some very interesting glazes, mostly nice light green celadon glazes very similar to Chandler’s glazes!

We selected the ones we liked most and mixed three or four of them in larger quantities, which all turned into lovely glazes, but over the next few firings I used them up.

The quest continues
So, back in August I set out on a journey that was part pilgrimage, part quest, and part a continuing science experiment to see what I could make out of this particular rock. I left early one morning, rendezvoused with Phil and another old friend, Rick Lynn, at a McDonald’s in Newberry, SC, and proceeded to Kirksey’s Crossroads.

Luckily for us, the owner of the land where the rock sits didn’t mind having three crazy pottery rockhounds tramping across his property. We were soon hacking at the rock before realizing it was a whole lot easier to pick up largish boulders that had already fallen off the igneous intrusion (probably a felsite) and put them into the bucket of the owner’s brand new Kubota tractor (not like in the old days…), before loading four totes that I’d put in the back of my van.

Chandler Rock outcrop

The outcrop

Rick Lynn, Phil Wingard, and me

Rick Lynn, Phil Wingard, and me

Sporting our CIA caps!

Sporting our CIA caps!

Phil doing all the hard work LOL

Close up of the Chandler rockClose up of the rock

Guys and rocks


Tractor of rocks‘n Roll

Van load of rock!Full van load of rock!

Glazing with Chandler Rock
Home again, home again, jiggety jig, to repeat the glaze making process with our foraged rock – calcining, tamping, ball milling, drying the powdered rock, making glazes, dipping pots, loading the kiln, firing it up, waiting in purgatory as the kiln cools.

Will we be in heaven or hell after we unload? One thing’s for sure, there will be more hard labor!

When thinking about how to glaze all the pots I’ve made over six months in preparation to fire them, I divide them into different groups.  I have several glazes that I like, not just the Chandler celadons, for instance, plain salt glaze, the Catawba Valley Alkaline Glaze, and glazes modified from Michael Cardew’s with whom I apprenticed, etc.

I hedge my bets, aware that some parts of my big kiln favor certain glazes, and place pots according to where I think they will be most likely to come out looking wonderful

Gas kiln loaded with rocks

Gas kiln loaded with rock and a few mugs

Calcified rock

After the firing, calcined rock

Close up of calcified rock

Close up


My intern, Dalton Hughes emptying the ground Chandler rock after ball milling

Spreading the rock to dry

Spreading the rock to dry

Dry rock

Dry rockPutting it awayPutting it away

Powdered rockPowdered rock to use to make the glaze

And finally – the firing!
Fate decreed Firing 106 to be one of the great ones, we got the kiln to top temperature and nicely reduced. All the Chandler Rock glaze experiments melted and look attractive.

Some of the labelling on the bottoms of the pots, painted in iron oxide, has bled, making the letters and numbers indistinct, so I’m not sure which glaze is on a particular pot, but for the most part I know which of the glazes are which.

Here are some of the pots glazed with Chandler Rock. The color variation depends the amount of reduction and salt each pot was subjected to in the kiln. The large bowls, for instance, were in a slightly hotter and smokier part than the jars. In a non-salt kiln the colors will most likely be darker. Even though the iron oxide markings identifying each glaze are blurry, I can just about decipher them 🙂

Chandler rock jar bottom of jar Chandler rock vase Chandler rock bowl Chandler rock bowl boittom of pot Chandler rock stein Chandler rock jar

These glazes aren’t perfect, they’re crazed and subject to minute fluctuations in reduction, oxidation, and temperature, but when everything aligns, they hold my attention in a way that other glazes don’t.

I have Michael Cardew, my master with whom I apprenticed (and who wrote Pioneer Pottery about his quest to make Asian-inspired glazes from local materials in West Africa in the 1950’s and 60’s) to partially thank for the insight about the qualities you can find when using local materials. I also have my own independent sensibilities refined over forty years of inquiry and practice here in the South.

Firing these subtle high temperature reduction glazes in a salt kiln, as I’ve done, is unconventional because the salt messes with the chemistry of the melting glaze materials as volatile fluxes fly through the atmosphere, bleaching the colors.

It’s like throwing herbs into a stew before serving, modifying the flavors in a way that isn’t entirely predictable. The process adds a further layer of mystery and creates something new, neither better nor worse, just different.

So, these results are only the beginning of the story.

I can’t wait to make a batch of flatware and mugs and glaze them in the Chandler Rock glazes and fire them in my gas kiln and see how they come out in a more traditional high-temperature reduction kiln, albeit not wood-fired.  I’m so excited!