Full Body Porcelain
As the name implies, this type of porcelain has the same surface as the body. There are two main versions, the speckled (salt & pepper) and the micronized grain version.
Multiple (Double) Loading Porcelain
Composed of fine speckled biscuit and micronized topping. The two layers are then pressed together.
Porcelain with Soluble Salts
Soluble salts composed of metal oxides and water are spread through a screen on white biscuit porcelain, which then penetrate the body of the tile and release colouring during the firing process.
Produced by applying thick layer of glazed (glass) on fine speckled biscuit after pressing. Glaze acts as sealant on top of the surface, but generally not heavy wear or scratch resistant.