n. (Hira=たま) ball, sphere; bulb; gem, jewel; bullet, shot; pretty girl; bead; testicle, testis, male reproductive organ located within the scrotum; noodle (before cooking) identifier

n. (Trad=玉, Pinyin=yu4) jade, jasper

adj. (Trad=玉, Pinyin=yu4) pure, beautiful

n. (Simp=玉, Pinyin=yu4) jade, jasper

adj. (Simp=玉, Pinyin=yu4) pure, beautiful

[獄] a prison; a jail; a gaol; a lockup

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[玉] (1) jade; jadeite; nephrite
(2) a precious stone; a gem; a jewel; a bijou

pao1 zhuan1 yin3 yu4
Throw a brick to attract jade.
A metaphor that means one might offer some rough idea or essay first, in order to arouse other people's better or more mature ideas to participate.

jin1 yu4 qi2 wai4, bai4 xu4 qi2 zhong1
Gold and jade on its outside, but rotten cotton on its inside.
Said of something superficially attractive but actually worthless. All that glitters is not gold. Compare with 外强中干 (wai4 qiang1 zhong1 gan1), 华而不实 (hua2 er2 bu4 shi2) and 半瓶子醋 (ban4 ping2 zi3 cu4).