Glaze yog qhov nruam cov vitreous txheej txuas mus rau cov ceramic nto. Hauv cov khoom siv dog dig zoo tib yam, cov cuab yeej xim ntawm cov hlau oxide tsuas yog siv los npaj cov dej ci rau ntau yam xim. Tus nqi ntawm cov hlau ions nws txawv, thiab cov hlau oxide nws tus kheej nthuav tawm xim sib txawv. Piv txwv li, hlau trioxide (Fe2O3) yog hmoov liab, thiab ferrous oxide (FeO) thiab ferroferric oxide (Fe3O4) yog hmoov dub.
Cov hlau oxide sib txawv tuaj yeem xaiv tau raws li kev xav tau. Ntxiv nrog rau cov xim muaj hlau ntau xim nws tus kheej, thaum hlau oxide ntxiv rau lwm yam ntsej muag, nws tuaj yeem ua rau cov ntsej muag ci nplua nuj thiab ci ntsa iab.
Piv txwv li, hlau oxide ntxiv rau ntxiv rau lub ntsej muag boric acid uas muaj alkali co xim kom qhia tau cov xim liab ntawm cov cawv; thaum hlau oxide ntxiv rau semi-matte thiab matte dawb ci, nws nthuav tawm cov duab ci ntawm lub teeb xim av, lub teeb daj thiab grey mus rau xim av tsaus; thaum thaum hlau oxide siv los ua kom daj daj, tsuas yog ob peb feem pua ntawm cov hlau oxide xav tau ntxiv txhawm rau qhia cov xim daj muaj zog.