porcelain
This term evokes an image of extreme fragility combined with a pristine, polished surface. It carries a strong connotation of luxury, delicacy, and high status, often associated with aristocratic tea sets or precious art objects. Because of its association with purity and a lack of blemishes, it is frequently used to describe skin that is pale and smooth.
While "ceramic" is a broad technical category, "porcelain" specifically suggests a level of translucency and refinement. In a social context, referring to something as porcelain often implies it is too precious or fragile to be handled roughly, shifting the meaning from a material description to a warning of vulnerability.
Uncountable when referring to the material itself (the vase is made of porcelain). Countable when referring to specific items made from the material (she collects porcelains).