Who can be called a "white crow" in society?

Never heard of this in UK. In which country do 'most citizens' use this expression?

I have heard of black sheep of the family but never white crow. I suppose they're basically the same thing.

RICK-N-BACHER, We have been called such names as "Black Sheep", "White Crow", "Bad Apple", "Misfit", "Oddball", "Double O" ("Ominous Omen"), etc. It used to bother me, now we proudly wear it as a badge of honor.

A brilliant idiom. It makes so much sense and is kinder than calling someone "strange". I also like the use of the word "unique" in the description. Being different makes the world a more colorful place.

Player #33161631, I am Canadian and I have never heard this expression before.

Player #33161631, not USA