Explanatory notes
… non-metallic materials which have been prepared and shaped previously at, in general, room temperature. Raw materials … the various constituents and, where necessary, milling, sieving, filter-pressing, kneading, maturing and de-airing. … as appropriate, specially prepared colours or opacifiers, vitrifiable enamels or glazes, slips, lustres, etc. Firing, …Legal note
… non-metallic materials which have been prepared and shaped previously at, in general, room temperature. Raw materials …