Kapangidwe kake ka mikanda yoyandama ndi silicon dioxide ndi aluminium oxide.Ili ndi zinthu zambiri monga tinthu tating'onoting'ono, tobowo, kulemera kopepuka, mphamvu yayikulu, kukana kuvala, kukana kutentha kwambiri, kutchinjiriza kwamafuta ndi retardant lawi.Amagwiritsidwa ntchito kwambiri m'modzi mwazinthu zopangira mafakitale a refractory.