Marquise Diamond Three Stone Engagement Ring in 14K Yellow GoldMarquise Diamond Three Stone Engagement Ring in 14K Yellow Gold. This modern engagement ring features a . 79 carat marquise cut diamond set in 14 karat yellow gold. The marquise cut has recently seen a surge in popularity. A rather shallow cut, marquise diamonds often appear larger than comparable weights of more traditional cuts. We refer to this design as the little black dress because it looks so great on everyone!