Clay & Materials
Every pot is a recipe before it is a form: clay minerals for plasticity, silica for structure, feldspar for melt. This page maps the clay bodies — earthenware, stoneware, porcelain and the purpose-built blends — the anatomy behind them, the five ways potters turn them into form, and the states clay passes through on its way to the kiln.
Kaolinite and ball clays. The plate-shaped particles that make clay plastic — and the skeleton the fire turns into ceramic.
Quartz, the glass former. Gives the fired body structure and hardness; in excess it makes ware crack at the quartz inversions.
The flux. Melts first, lowers the body's maturing point and welds clay and silica into glass — vitrification is feldspar at work.
Pre-fired, ground clay. Adds tooth and stand, cuts shrinkage and warping, and arms a body against thermal shock.
Earthenware
The oldest and most widespread family. Iron-rich and often terracotta red, it matures at low temperatures and stays porous — the glaze is what makes it watertight. Forgiving to form, cheap to fire, and home to the brightest glaze palette in ceramics, from majolica to luster.
Stoneware
The workhorse. Fired to vitrification it becomes dense, strong and watertight even before glaze; its buff-to-toast body flatters bare clay and glaze alike. Most functional potters live here — stoneware takes throwing, handbuilding and daily use in stride.
Porcelain
Kaolin, feldspar and silica — the whitest, tightest body. Fired high it vitrifies to near-zero absorption, turns translucent where the wall is thin, and rings like a bell when struck. It is also the least forgiving clay: short, thirsty, quick to slump — and it remembers every uneven touch through drying and both firings.
Specialty bodies
Purpose-built blends. Raku bodies load up on grog to survive thermal shock; paper clay laces any body with cellulose fiber so greenware turns tough and dry-to-wet joins become possible; sculpture bodies go coarse and open so thick walls dry and fire without cracking.
Centering, opening, pulling: the wheel turns months of muscle memory into round, thin-walled forms at speed. The fastest route to repeated cylinders, bowls and plates — and the slowest skill to earn.
A ball of clay opened with the thumb and thinned between the fingers. The most direct conversation with the material — every potter's first pot starts as one warm handful.
Rolled ropes of clay stacked, joined and smoothed. Slow and unlimited: coils build anything from a cup to a human-height vessel without a single machine.
Clay rolled into even sheets, cut against templates and assembled leather-hard, like tailoring. The architect among the techniques: boxes, plates, angular geometry — and joins that must be scored, slipped and dried slowly.
Liquid clay poured into plaster molds; the wall builds where the plaster draws water out, and the excess pours off. Identical multiples with perfectly even walls — the real craft lives in the mold-making.
≈ 20 – 25 % water. Form it: throw, pinch, coil, roll.
Trim feet, attach handles, join, carve — the joining window.
The weakest state — handle like glass. Ready for bisque.
Fired once (≈ cone 08 – 04): hard, porous, drinks glaze.
Glaze-fired to maturity: dense, finished, permanent.
Clay shrinks about 10 – 15 % from wet to glaze-fired, body-dependent — fire test tiles before committing to a form.
Firing ranges, cones and absorption figures are typical supplier values; the data sheet of your specific body takes precedence.