Use our diamond education to learn about Oval Cut, 4 Carat diamonds, and browse our broad selection of loose stones. Oval Cut, 4 Carat diamonds are versatile enough to suit a timeless solitaire engagement ring or a vintage-inspired halo setting. You can trust that our loose diamonds are certified and conflict free; each one comes with a detailed AGSL or GIA grading report. If you run into any questions during your purchase, you can consult our detailed diamond education or get expert advice from our virtual gemologist. Once you've chosen your stone and built your one-of-a-kind engagement ring, you can preview it obligation-free at one of our many local jeweler partners.