Noun
aluminosilicate (plural aluminosilicates)
(inorganic chemistry) Any of many silicate minerals, such as feldspar and zeolite, in which a proportion of the Si ions are replaced by Al, the excess negative charge being balanced by extra sodium, potassium or calcium ions.
For this reason, most have a bulb of fused silica (quartz), but sometimes aluminosilicate glass. Source: Internet
The high temperatures cause the salt to volatize, depositing it on the surface of the ware to react with the body to form a sodium aluminosilicate glaze. Source: Internet