Like her mother, she's grey (5)
I believe the answer is:
pearl
'grey' is the definition.
(thesaurus)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for pearl that I've seen before include "Gem; size of type" , "Object of great worth" , "finest example" , "Off-white colour" , "greatly valued" .)