ZrSiO₄, natural silicate of zirconium found in Brazil and elsewhere. One such deposit known as brazilite is said to contain about 80% zirconium oxide in a semimanufactured form. This product is employed as a refractory in the making of "zirkite" bricks and cement. In rare cases, used as a cobalt groundcoat constituent. Zirconium silicate is used in formulation of zircon enamels that depend upon crystallization of zircon compounds for opacity development.