Duty exemption for zirconium and yttrium oxides imported for manufacture of cubic zirconia; reduces customs and additional duty obligations. Exempts zirconium oxide and yttrium oxide imported for manufacture of raw cubic zirconia by limiting basic customs duty to that calculated at the rate of 35 per cent ad valorem (waiving any excess) and by wholly exempting the additional duty under section 3 of the Customs Tariff Act; exemption exercised under section 25(1) of the Customs Act and confined to items in Chapter 28 of the First Schedule.