Jade is notable for its combination of hardness with soft luster. This counsel… he will be mild and pure, like precious jade. Thus the work finds favor in the eyes of the Deity.
Wilhelm identifies jade’s symbolic core as the paradoxical union of hardness and soft luster, making it the ideal emblem of counsel that is both firm and gentle, thereby winning divine favor.
, The I Ching or Book of Changes, 1950thesis