I mistakenly thought that De Beers would be mass market because it's the world's largest diamond producer. Yvan, one of their “brand ambassadors” impressed me with his knowledge, his willingness to educate me, and the suaveness with which he kept slipping diamonds on and off my bare, and very virgin, left ring finger. I swooned. Yvan was pushing the round cuts—the priciest rings—which were a bit boring for my taste. I preferred the 1.77-carat cushion-cut solitaire (F color, VS2 clarity). It looked really clean, tidy, and modern. But I'm more label conscious than I'd like to admit, and the De Beers name didn’t have the right cachet. 703 Fifth Ave., nr. 55th St.; 212-906-0001.