The phrase 'A Diamond in the Rough' refers to someone or something whose good qualities are hidden.
Example of Use: "This film is one of those diamonds in the rough - a wonderful gem that almost no one has noticed."
Interesting fact about A Diamond in the Rough
If you’ve ever seen an uncut diamond (a diamond in the rough,) you know it looks nothing like the sparkling gemstones found adorning rings and other jewelry. The origin of the idiom 'a diamond in the rough' isn’t known, but it’s safe to say that the term was used as early as the 1600s; a similar term first appeared in print in John Fletcher’s 1624 A Wife for a Month: “She is very honest, and will be as hard to cut as a rough diamond.”
