Mexican Fire Opal, Diamonds 18K Yellow Gold, Ring, R 0029-58/118 Karat Yellow Gold, Mexican Opal, Diamonds Ring Mexican Opal 3. 53 ct Diamonds 0. 49 ct This ring showcases the unique beauty of opals, which cannot be cut like other stones. With a 3. 53 carat Mexican Fire Opal set in 18K yellow gold and accented with diamonds, it effortlessly conforms to the stone's shape, resulting in a harmonious and one of a kind piece. US Size 7 1 4 EU Size 54 5 8 21. 30 x 28. 40 mm Weight 7. 64 gm