Shop › Australian Opal 3.25 ct. w/ 0.85 cts. Diamond Platinum Ring Size: 6.75 Image 1 of 6 Image 2 of 6 Image 3 of 6 Image 4 of 6 Image 5 of 6 Image 6 of 6 Australian Opal 3.25 ct. w/ 0.85 cts. Diamond Platinum Ring Size: 6.75 $5,990.00 Australian Opal (3.25 ct) and Diamond (0.85 cts) Solid Platinum PL900 Ring. Add To Cart Added! Australian Opal (3.25 ct) and Diamond (0.85 cts) Solid Platinum PL900 Ring.