"Alumina, or Oxide of Aluminium, is one of the most abun- dant of earths. Combined with silica it is the chief constituent of kaolins and China clays. It imparts refractory qualities to clays and is an indispensable ingredient of pure glazes. Pure alumina or calcined Aluminium is a chemical product."@es . . "Alumina"@es . "Pottery and porcelain: \u00CDndice adicional"@es . . . . "Alumina, or Oxide of Aluminium, is one of the most abun- dant of earths. Combined with silica it is the chief constituent of kaolins and China clays. It imparts refractory qualities to clays and is an indispensable ingredient of pure glazes. Pure alumina or calcined Aluminium is a chemical product."@es . "Alumina (Pottery, for artists)"@es . "Alumina"@es . . .