She's a gem (4)
I believe this clue is a double definition.
'she's' is the first definition.
'a gem' is the second definition.
(I know that ruby is a type of gem)
(Other definitions for ruby that I've seen before include "killed an assassin" , "A red jewel" , "Girl's name - colour" , "Jack perhaps" , "Vivid red" .)
(Other definitions for beryl that I've seen before include "Girl's name - jewel" , "Gemstone of which emerald is a variety" , "- Bainbridge, English novelist" , "Gemstone (for Ms Bainbridge?)" , "Girl's name - gemstone" .)