Glossary [17]
plasticity: properties of some materials like metals and polymers to undergo permanent deformation by work or rather intense external stress.
pomice stone: eruptive effusive rock (pomice). Its characteristics are lightness, roughness, porosity. It contains numerous small cavities due to exits of gaseous substances during the consolidation phase. Pomice stones, after being finely ground, are used as abrasives for example in polishing marble.
porcelain: porcelain is a kind of ceramics which is distinguished in two varities; hard and soft. The hard porcelain consists of kaolin, feldspar quartz and chalk mixed together. Very compact, hard porcelain is impermeable, white and has a vitreous translucid structure. Soft porcelain is different from hard porcelain because other types of clay replace the koalin.
porcelained stoneware: porcelained stoneware is stoneware that is enamelled, coated in white translucent enamel. Porcelained stoneware is widely used in flooring because it has excellent technical features including low water absorption (up to 0.05%) and a high mechanical resistance. All ceramics like terracotta and porcelain can be enamelled.
porosity: characteristic of a material of being porous, full of holes. Marble, given its porosity, tends to absorb oily substances and for this is generally submitted to particular treatments before and after it is laid.
