来自于权威FCRF彩钻指数网站上，关于彩钻厚度的观点，和我的想法又一次一致。

The depth of a diamond refers to the height of a stone divided by its width. Fancy color diamonds with low depth percentage are greatly valued as they look larger than their actual weight (this is true as long as the color distribution of the stone is not compromised because of the shallowness of the diamond). Very shallow stones earn a premium because of their rarity. Most fancy color diamonds are cut with a high depth percentage, so when we see a shallow stone with excellent color retention, it deserves a premium.