Explanatory notes
… treatment of oxides (of antimony, silver, arsenic, copper, chromium, cobalt, etc.) or salts (fluorides, phosphates, … of silica with other products (feldspar, kaolin, alkalies, sodium carbonate, alkaline-earth metal compounds, lead … of opacifiers or pigments; sometimes substances (e.g., titanium or zinc oxides) are added which produce decorative …