Grolleg Kaolin

Grolleg is chosen for what it does not contain. Titania scatters and absorbs light, and it takes very little of it in a body to dull a thin porcelain wall. Grolleg is very low in titania. Its iron is ordinary for a kaolin, and iron is not what decides translucency. It also contains residual mica, which brings some potassium with it, so the clay contributes a little flux of its own. Its plasticity is moderate, so a body built on it usually needs a plasticiser as well. Translucency is still a property of the fired body and not of the clay alone. Wall thickness, flux level and firing all decide it.