Toi et Moi London Blue Topaz and Lab Alexandrite Cocktail Ring - 18K White Gold. Shimmering in hues of brilliant blue and alluring purple, this rare toi et moi ring is as on trend as can be and features a London Blue topaz and a lab alexandrite as a perfectly matched pair. This Limited Edition, rare-find item is crafted only in small quantities and features an exclusive, of-the-moment design created with high-quality gemstones, meticulous craftsmanship, and ethical sourcing.