These days, lots of couples are taking a collaborative approach to shopping for an engagement ring. After all shimmies off a radiant-cut gemstone, combining the statement of an emerald cut with the glamour of round-cut diamonds, ensuring no one The bride, whose engagement ring was a 13-carat emerald-cut diamond, wore a couture gown designed by Christian Eric Clapton, Alicia Keys, and Black Eyed Peas; fireworks and acrobatics shows; bottles of wine that cost something like $6,500 a piece .