Natural diamonds graded on the GIA fancy-colour scale as Fancy Brown, with brown the dominant colour and no colour letter. Shoppers call these champagne or cognac depending on depth; the GIA grade is the wording that matters. Listed here only when the stone costs less per carat than an untinted diamond of the same size, so the comparison price on each card is the champagne discount against a near-colourless G–H stone.
What a brown notation takes off a champagne diamond's price, where the discount is widest by carat weight, and how the two savings figures differ.
Champagne, fancy brown and chocolate diamonds are three products. How the D-to-Z brown notation discounts a stone, and why the fancy browns here cost less.
A photograph cannot tell you a diamond is brown; the GIA report can. The two rules that admit a stone here, and how to check any one yourself.