A true sight to see, Emerelle Collection's truly unique engagement ring combines round and emerald-cut diamonds in a square three-stone pattern (2-1/2 ct.t .w.). Crafted in 14k white gold. 2-1/2 Carat Diamond Engagement Ring. Diamond Color Rating Code: I-J. Diamond Clarity Rating Code: SI-SI2. Diamond Cut: Round and Emerald. Almost all gemstones and blue and black diamonds have been treated to enhance their beauty and require special care. All gemstone carat weights (ct. t.w.), if mentioned, are approximate; variance may be .05 carat. Ring Sizer.