Shop our selection of Cushion Cut, 4 Carat diamonds to build a custom engagement ring. You can rest assured that Ritani diamonds are the best quality; each one comes with a detailed GIA or AGSL certification report. After selecting your stone, browse our wide range of engagement ring metals and styles, from Art Deco-inspired diamond halos to timeless solitaire settings. For expert advice and guidance on choosing your diamond, you can contact our customer service team or use our non-commissioned virtual gemologist service. With Ritani's free in-store preview program, you can view your diamond or custom engagement ring obligation-free at any of our authorized local jewelers in the US.