noun
or zirconium dioxide
: a refractory crystalline compound ZrO 2 that occurs in nature as baddeleyite, that is usually obtained as a heavy hard white insoluble powder by heating zircon with carbon in an arc furnace and burning the product in air, and that is used chiefly in refractories (as crucibles and cements), in thermal and electric insulation, in abrasives, in enamels and glazes as an opacifying pigment, and especially formerly in incandescent lamps because of its brilliant luminosity when heated — called also zirconia