All of these Mason stains make the porcelain more refractory, but some more so (e.g. 6385, 6226). Some do not develop the intended color (e.g. 6006 pink). Some need a higher concentration (e.g. 6121, 6385). Some need a lower concentration (e.g. 6134). Some do not impart a homogeneous color (e.g. 6385).
Ceramic stains are manufactured powders. They are used as an alternative to employing metal oxide powders and have many advantages.
In the ceramic industry, refractory materials are those that can withstand a high temperature without deforming or melting. Refractories are used to build and furnish kilns.