Ceramics vs pottery: what is the difference?
Pottery is a type of ceramic, not a rival to it. Ceramic is the whole family of fired clay and mineral objects; pottery is the branch made from clay on the wheel or by hand. The real differences show up in the clay body and the cone it fires to.
Is pottery the same thing as ceramics?
No. Ceramic is the umbrella term for anything made from clay or mineral powders that is hardened by heat, from a coffee mug to a floor tile to a spark plug. Pottery is one branch of that family: functional or decorative ware formed from clay. Kiln Frog puts it simply, ceramics covers a range of fired materials, while pottery is clay fired in a kiln until it hardens. When a studio potter says "my ceramics," they almost always mean their pottery. The words overlap in daily use, and that is fine.
What are the three types of pottery clay?
Almost all studio pottery is one of three clay bodies: earthenware, stoneware, or porcelain. They are not brands or styles. They are clays that vitrify, meaning turn glassy and dense, at different temperatures. That firing temperature is the single fact that changes how the pot behaves.
| Clay body | Matures at | Temperature | Character |
|---|---|---|---|
| Earthenware | cone 06 to 04 | 1830 to 1940 F | Porous, bright, low-fire |
| Stoneware | cone 5 to 7 | 2160 to 2280 F | Dense, waterproof, mid-range |
| Porcelain | cone 9 to 11 | 2340 to 2400 F | Thin, white, high-fire |
Earthenware
Earthenware is low-fire clay. It matures around cone 06 to cone 04, roughly 1830 to 1940 F, and it stays a little porous even after firing. Left unglazed it will slowly wick water, so earthenware meant to hold liquid gets glazed and fired again. Terracotta plant pots are the classic bare earthenware. The upside is bright color and a low, forgiving firing. The trade-off is a softer, more absorbent body than the others.
Stoneware
Stoneware fires hotter, usually cone 5 to cone 7, about 2160 to 2280 F, and vitrifies into a dense, hard, waterproof body. Once it is fired to maturity it holds water even without glaze, which is why so much everyday dinnerware and mugs are stoneware. Cone 6 stoneware in an electric kiln is the most common setup in home and community studios today. It is durable, chip-resistant, and the glazes at that range are well documented.
Porcelain
Porcelain is high-fire clay made from refined materials like kaolin. It matures around cone 9 to cone 11, roughly 2340 to 2400 F, and fires to a dense, nearly glassy body that can be thin enough to let light through. It is the least forgiving to throw and fire, and it rewards the effort with strength and a clean white surface. If a piece is thin, white, and rings when you tap it, it is usually porcelain.
Why the firing temperature is the thing that matters
The name on the clay bag matters less than the cone you fire to. Vitrification is the point where the clay particles fuse and the pot stops being porous. Fire a clay too low and it stays weak and absorbent. Fire it past its cone and it can slump, bloat, or stick to the shelf. That is why a firing schedule is written around a target cone, not a target style.
Two numbers help keep this straight. Earthenware and stoneware often share the same bisque firing, a slow low fire near cone 06 that drives out water and organics and leaves the ware porous enough to soak up glaze. The clays part ways at the glaze firing, when each climbs to its own maturing cone. You can see the full ladder of cones and temperatures in the Orton cone chart, and the reason for the two separate firings in the guide on bisque versus glaze firing.
How do I know which clay I am using?
Read the bag. Clay is sold with a firing range printed on it, like "cone 06 to 04" for earthenware or "cone 5 to 6" for mid-range stoneware. Match your kiln program to that range and fire a witness cone to confirm the kiln actually reached it. If you have a finished pot and no bag, the tells are rough: a porous, often reddish, easily scratched body points to earthenware, a dense grey or brown waterproof body points to stoneware, and a thin, white, translucent body points to porcelain.
When you know your cone, the rest is just the schedule. Pick your clay target in the firing schedule builder and it lays out the ramps and holds for that cone, whether you are firing a batch of earthenware planters or a set of cone 6 mugs. For the mid-range setup most electric kilns run, the cone 6 glaze firing schedule is the place to start.
The short version
Ceramics is the family. Pottery is the clay branch of it. Within pottery, earthenware, stoneware, and porcelain are three clay bodies that differ mainly by the cone they fire to: low for earthenware, mid for stoneware, high for porcelain. Get the cone right and the pot comes out strong and watertight. Get it wrong and no clay name will save it.
Sources
- Kiln Frog, Pottery vs Ceramics (kilnfrog.com).
- Orton pyrometric cone temperature chart, ortonceramic.com.
Build your firing schedule
Pick your clay cone, choose bisque or glaze, set a speed, and print the ramp and hold sheet free.