What is ceramics? Ceramics is the family of hard, inorganic, nonmetallic materials that are shaped and then hardened by heat, and the word also names the objects made from them and the craft of making them. Clay pottery, bricks and bathroom tiles are ceramics, and so are many materials that contain no clay at all, such as the insulator in a spark plug or the zirconia in a dental crown.
This guide is research-based. It draws on the American Ceramic Society, the University of Maryland materials science department, Wikipedia's overview of ceramics and kaolinite, and the Orton cone chart. It explains the material science in plain terms for hobby potters, and links to our other guides where they go deeper.
What is ceramics? Two meanings
People use the word in two main ways:
- A class of materials. In science and industry, ceramics are solids that are neither metal nor organic (plastic, wood or other carbon-based matter). The American Ceramic Society describes them, broadly, as nonmetallic, inorganic, crystalline materials, and counts oxides, nitrides, carbides and borides among them.
- An art and craft. In a school, art center or gallery, "ceramics" means making things from clay: hand-building, wheel throwing, glazing and firing. A ceramics class and a pottery class usually teach much the same skills.
Both meanings share one idea: a mineral material is shaped and then changed for good by heat. Our what is pottery guide covers the clay-vessel side in detail.
Where the word comes from
"Ceramic" comes from the Ancient Greek keramikos, "of or for pottery," from keramos, meaning potter's clay, tile or pottery. So the word started with pots and grew to cover a much wider set of materials as engineers learned to make heat-hardened solids from powders other than clay.
What are ceramics made of?
Ceramics split into two broad groups by raw material. Wikipedia and the American Ceramic Society both draw this line between traditional and advanced (technical) ceramics.
Clay-based (traditional) ceramics
Traditional ceramics start with clay, usually blended with silica (quartz) and feldspar. Earthenware, stoneware, porcelain and bone china are all in this group, along with bricks, roof tiles, sewer pipe and bathroom fixtures. The American Ceramic Society's list of traditional ceramics also takes in refractories (heat-proof linings for furnaces and kilns), abrasives and cements. Our guide to what clay is made of explains the minerals in pottery clay.
Non-clay (advanced or technical) ceramics
Advanced ceramics are made from purified or synthetic powders, often with no clay at all. Common examples:
- Oxides: alumina (aluminum oxide) and zirconia (zirconium oxide). Zirconia is used for knife blades and fuel cells.
- Carbides: silicon carbide and tungsten carbide, valued for hardness and wear resistance.
- Nitrides and borides: such as silicon nitride, used where parts face heat and wear.
The American Ceramic Society groups advanced ceramics into medical ceramics, electroceramics, optical ceramics and structural ceramics.
How heat turns clay or powder into ceramic
Every ceramic is made the same basic way: shape a powder or plastic mass, dry it, then heat it until the particles bond. In clay, the first permanent change is chemical. Kaolinite, the main mineral in many clays, loses its chemically bound water at about 1,020 to 1,110°F (550 to 600°C), and above about 1,920°F (1,050°C) new crystals such as mullite begin to form, according to published mineral data. Once clay has passed that first change, water can no longer turn it back into mud.
Two words describe what happens next:
- Sintering: particles bond at their points of contact and the piece shrinks and densifies, without fully melting. Many technical ceramics are made this way.
- Vitrification: part of the body melts into glass that fills the gaps between particles. Stoneware and porcelain fired to their cone become dense and absorb very little water because of this glass.
Pottery glaze is a separate thin layer of glass melted onto the surface in the same kind of firing. Potters track firing heat with pyrometric cones rather than a single temperature, because time matters as well as heat; cone 6, for example, is 2,232°F (1,222°C) on Orton's chart at 108°F an hour. Our pottery cone chart lists the full range, and our kiln guide explains how kilns reach it.
Properties of ceramics
The same chemistry gives ceramics a recognizable set of traits. Wikipedia's summary and the American Ceramic Society agree on the main ones:
| Property | What it means | Where you notice it |
|---|---|---|
| Hard | Resists scratching and wear | Tile floors, cutting tools, grinding wheels |
| Brittle | Strong when squeezed, weak when bent or struck; cracks instead of denting | A dropped mug breaks rather than bends |
| Heat resistant | Keeps its shape at temperatures that melt many metals | Kiln bricks, furnace linings, oven dishes |
| Insulating | Usually a poor conductor of heat and electricity | Spark plug insulators, power line insulators |
| Chemically inert | Resists rust, acids and many chemicals | Lab ware, sinks, toilets, dental work |
There are exceptions. Some ceramics are semiconductors, some are piezoelectric (they make a voltage when squeezed) and some are superconductors, which is why ceramics turn up inside electronics. Brittleness can also be reduced with toughened compositions, which is how ceramic body armor and bearings work.
Is glass a ceramic?
Sources differ, and it is fair to say so. Wikipedia notes that many ceramics experts do not classify glass as a ceramic, because glass is amorphous (no regular crystal structure) while most ceramics are crystalline. The American Ceramic Society, on the other hand, treats ceramics and glass as one field and describes glasses as noncrystalline materials that share ceramics' hardness, chemical resistance and insulating behavior. Glass-ceramics sit in between: glass that is heat treated until part of it crystallizes, used for things like cooktops.
Research note: the American Ceramic Society defines ceramics as crystalline and handles glass alongside them as a sister material; Wikipedia reports that many experts exclude glass. For a potter the practical point is the same either way: glaze is a glass layer fused onto a ceramic body.
Everyday ceramics
Most people handle ceramics dozens of times a day without thinking about it:
- Tableware: stoneware mugs, porcelain plates, earthenware bowls.
- Whitewares and sanitaryware: sinks, toilets and wall tiles.
- Structural clay products: bricks, roof tiles, clay pipe and floor tile.
- Cement and concrete: counted among traditional ceramics by the American Ceramic Society.
- Refractories: the firebrick inside a pottery kiln, a fireplace or a steel furnace.
Technical ceramics
Advanced ceramics do jobs metals and plastics cannot. The University of Maryland materials science department and the American Ceramic Society list examples that include:
- Spark plugs, catalytic converter substrates and race car brakes
- Heat-resistant tiles on the space shuttle
- Artificial joints, bone scaffolds and dental crowns
- Body armor, cutting tools and bearings
- Fiber optics, touch screens, chips, lasers, solar cells and solid-state batteries
- Cooktops and sporting goods such as skis and golf clubs
None of these come out of a home pottery kiln. They are made from engineered powders under tight factory control, but they rely on the same basic idea of shaping a mineral material and fusing it with heat.
Ceramics as an art and a hobby
For most readers of this site, ceramics means the studio craft. A ceramics course usually covers hand-building (pinch, coil and slab), wheel throwing, surface decoration with slips and underglazes, glazing and firing. Many art schools call their clay department "ceramics" because students make sculpture and tiles as well as vessels.
At home, studio ceramics comes down to three choices: a clay body, a way to shape it and a kiln (your own or a studio's) that reaches the clay's cone. Our types of pottery clay guide explains earthenware, stoneware and porcelain, and our clay and glaze guide covers how glazes are matched to clay.
Ceramics and pottery in one paragraph
All pottery is ceramic, but not all ceramics are pottery. Pottery is fired clay ware, mostly vessels; ceramics also includes bricks, tiles, glass-like and technical materials. Our ceramics vs pottery comparison covers the word choice and the "is clay ceramic" question in full.
Common misconceptions
- "Ceramic means made of clay." Traditional ceramics are, but zirconia, alumina and silicon carbide parts contain no clay.
- "Air-dry clay makes ceramics." It never goes through firing, so it stays unfired clay held together by binders.
- "Ceramics cannot take heat changes." They resist high heat well, but sudden temperature swings (thermal shock) can crack them, which is why kilns heat and cool on a schedule.
- "Hard means unbreakable." Ceramics are harder than steel in many cases yet far more brittle.
Safety for home ceramics
The raw materials that make ceramics tough are the same ones to handle with care. Dry clay and glaze dust contain crystalline silica, so wet clean surfaces instead of sweeping and wear a NIOSH-approved respirator when mixing dry clay or glaze materials. Read the maker's safety data sheet (SDS) for each glaze and raw material, and do not assume a glaze is food safe on your own pots: go by the maker's label and fire to the stated cone.
Kilns reach ceramic temperatures and get hot on the outside. Follow the maker's clearance and venting rules, use the electrical figures the maker publishes, and have a licensed electrician check or install the circuit.
What you need
To make ceramics at home, start with a kiln clay that matches the cone of the kiln you will use and a firing plan, such as a community studio. Our guide to starting pottery at home walks through the setup, and our best clay for pottery guide compares clay bodies for beginners.
Sources: American Ceramic Society, "What Are Ceramics?" (definition, traditional and advanced branches, glass, applications); University of Maryland Department of Materials Science and Engineering, "Ceramics" (definition, properties, examples); Wikipedia, "Ceramic" (word origin, classification, properties, glass debate, technical examples) and "Kaolinite" (dehydration and mullite temperatures); Digitalfire glossary, "Ceramic"; Orton Ceramic Foundation temperature equivalents chart for self-supporting cones. Specs checked October 2026.