CLOCKWISE FROM TOP LEFT: 1.44-carat natural “fancy pink” marquise-cut diamond ring in platinum and 18k rose gold with pavé-set diamonds, Premier Gem for Forevermark (price on request). King Jewelers, 18265 Biscayne Blvd., Aventura, 305-935-4900. Platinum and white-diamond Josephine ring with pink diamond, Van Cleef & Arpels (price on request). Bal Harbour Shops, 9700 Collins Ave., 305-866-0899. 18k yellow-gold and platinum ring with white diamonds and 4.90-carat fancy yellow-diamond center stone, Bulgari (price on request). Bal Harbour Shops, 305-861-8898

With roughly 10 percent of all US engagements taking place on Valentine’s Day, there likely will be quite a few bended knees in South Beach restaurants this month. How to truly ensure a “yes” and not public humiliation? Opt for that rarest of diamond categories, the fancy-colored stones that are increasingly dazzling sophisticated eyes. It’s amazing to think that fancy colors were once considered the ugly stepsisters of the diamond set, taking a backseat to white, or colorless, diamonds; these days, nearly every shade under the sun is all the rage in both taste and investment quality. Indeed, a survey of recent auctions at Christie’s and Sotheby’s finds colored diamonds far surpassing estimates—proving that even if the “I do” doesn’t last forever, the value of the rock surely will.

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