The coloured pigments are mixed with glass flux for application. Tableware, especially bone china and porcelain are usually decorated in this way. It was discovered early on that substances derived from plants were destroyed by high temperatures. Our predecessors had to find pottery colouring materials in the sands and rocks and in the earth. The names of semi-precious minerals, for example garnet, zircon and others are used in the names of some ceramic pigments, giving a clue to their origin.
Natural minerals are the basis of most of the colours used today.
They are mainly metallic oxides, and according to one ceramic colour manufacturer, they can give rise not just to the seven colours of the rainbow, but to about 20,000 visibly different shades of colour when they are used in various combinations. Shades of pink, blue, grey, yellow and white are the most likely to include tin-containing pigments. Colour manufacturers keep their exact formulations secret, but the most common ingredients are well known. Blue Traditionally associated with the element cobalt. Green Often obtained from chromium compounds.