London Blue Topaz and Diamond Halo Ring Blue Topaz 3.8 ct. Diamond 0.43 ct. 18K White Gold Other Products. Two Rows Diamond Ring Two Rows Diamond Ring in 18K White Gold More Detail Diamond Studs Earrings Round Diamond 0.72 ct. Baguette Diamond 0.79 ct. 18K White Gold More Detail Diamond Ring Diamond 0.18 ct. Pave Diamond 0.13 ct. 18K White Gold More Detail Solitaire Ring 18K White Gold More Detail