Shininess is one property people appreciate in gems, but not the only one. Many so-called fine things are loved exactly because their quality can’t be pinned down on a simple scale, but rather is a blend of subjective evaluations whose weightings are constantly evolving as tastes change.

Is the best wine the one with the highest alcohol content? The best chocolate the one with the most cocoa or the most sugar? The best painting the one with the most contrast? Etc.