I spent two weeks shopping in-store before buying online. I asked every jeweler the same question: "What does ideal cut mean?" Answer 1 (chain store): "It means GIA Excellent grade — the highest cut quality GIA certifies." Answer 2 (independent jeweler): "It's a marketing term. Different retailers define it differently. There is no universal standard." Answer 3 (diamond dealer): "Ideal is the original AGS 000 standard. GIA Excellent is broader. True ideal is a subset of Excellent." Answer 4 (boutique): "We use it to mean our best stones — Hearts and Arrows pattern, verified by ASET scope." Answer 5 (mall jeweler): "Ideal, Excellent, Super Ideal — these all mean basically the same thing." Answer 6 (estate jeweler): "Tolkowsky's 1919 mathematical ideal proportions. Almost nobody cuts to that exact standard today." All six answers contain partial truth. Here is the complete picture: • "Ideal" has no legal or certification definition. Any retailer can use it for any stone. • GIA Excellent is the highest cut grade GIA issues. It covers a range — not a single point. • AGS 000 (Triple Zero) is a more precise standard from the American Gem Society. Narrower than GIA Excellent. • Hearts & Arrows is a visual pattern created by precise cutting. It is evidence of superior craftsmanship but is not a grade. • Super Ideal / True Ideal are retailer-coined terms, often (but not always) referring to Hearts & Arrows stones with ideal proportions. When a jeweler says "ideal cut": ask them what standard they are using. If they cannot answer precisely, that tells you everything.