a rough diamond

基本解释

Typically, about 60 percent of a rough diamond is lost as dust or shavings in the cutting process.
典型区别就是，原石大约60%的部分会作为粉尘除去或是在切割过程中成为碎料。
He's not a rough diamond--a pearl-containing oyster of a rustic: he's a fierce, pitiless, wolfish man.
他不是一块粗糙的钻石——乡下人当中的一个含珠之蚌，而是一个凶恶的，无情的，像狼一样残忍的人。我从来不对他说，‘放开这个或那个敌人吧，因为伤害他们是不正大光明的，残酷的。’
He said I was like a rough diamond and I needed polishing.
他说我就像一块粗糙的钻石，需要磨光。

"A rough diamond is pure potential and pure risk, " writes Hart.
FORBES: Fracture Lines
McQueen the teenager lacked the academic credentials for admission, and by Hillson's tell, he was still a very rough diamond at 21.
FORBES: Fashion's Hard Case
De Beers Group reports that high prices and strong demand in India, China, the Middle East and, surprisingly, the U.S. has resulted in a record for rough diamond sales.
FORBES: De Beers Diamond Sales Up 33%