A mix of diamonds shine in this stacked white gold ring from Marco Bicego's Goa collection. 18K white gold/diamonds. Made in Italy. Diamond: 0.41 ct. T.w. All gemstone carat weights (ct. T.w.) are approximate; variance may be .05 carat. Almost all gemstones and black diamonds have been treated to enhance their beauty and require special care. Ring Size Chart. Photo may have been enlarged and/or enhanced.