“他山之石”英文比较确切的翻译应该是什么？

他山之石,可以攻玉
advice from other may help one overcome one's shortcomings

有一个常用的俚语：the grass is always greener on the other side， 直译：那边的草总比这边绿，这山望着那山高，他山之石的意思。

F.Y.I.

The stone from another hill can cut the jade.

By other's faults, wish men correct their owe! 他山之石 可以攻玉

advice from others may help one overcome one's difficulties.
(补充2楼的）