What does the image of "jade" in The Book of Songs mean?

In ancient times, jade symbolized noble moral character in ethics, and Confucianism had the view that "a gentleman wins victory over jade". The theory that "the beauty of jade has five virtues" in the Eastern Han Dynasty is to compare the five physical attributes of jade to the five moral qualities of human beings: "benevolence, righteousness, wisdom, courage and cleanliness". Etiquette function of ancient jade has always been the mainstream of ancient jade in China. "Six vessels" are the main jade used for etiquette in feudal society, that is, six kinds of jade with different shapes are used for ritual activities such as sacrifice, engagement, military service and so on. This is what Uncle Zhou Li said: "Jade is a six-vessel, which presents the world, faces the sky with pale walls, presents the east with yellow, presents the south with green, and presents the west with red."