While the classic Round Brilliant continues to reign supreme as the most sought-after diamond shape for engagement rings nationwide, shifting tastes are giving rise to new favorites. Across the U.S., ...

While the classic Round Brilliant continues to reign supreme as the most sought-after diamond shape for engagement rings nationwide, shifting tastes are giving rise to new favorites. Across the U.S., ...

A model shows 'The Sky Blue Diamond' ring at the auction house Sotheby's in London, Tuesday, Oct. 11, 2016. The mesmerizing and rare vivid blue diamond weighs 8.01 carats, mounted by Cartier, will be ...