Australian Doublet OpalFull Details: Australian Opal Loose Opal Doublet Colour Royal Blue Green Shape Oval Weight 0. 81 Carats Width 4. 51 MM Length 7. 48 MM Height 3. 18 MM This beautiful one of a kind piece is a combination of the rich, radiant, crystal colours of 'Lightning Ridge, NSW' known worldwide to have the highest quality opal available, coupled with the ever irresistible Ironstone Opal from the depths of Queensland that gives you a piece that's everlasting.