- a mineral of the feldspar group, potassium aluminum silicate, KAlSi3O8, identical in composition with orthoclase but having triclinic instead of monoclinic crystals, used in making porcelain.
- a white, creamy yellow, red, or green mineral of the feldspar group, found in igneous, sedimentary, and metamorphic rocks: used in the manufacture of glass and ceramics. Composition: potassium aluminium silicate. Formula: KAlSi 3 O 8 . Crystal structure: triclinic