A gem of a girl? (5)
This clue is a double definition.
'a gem' is the first definition.
(beryl is a kind of gem)
'a girl?' is the second definition.
'of' acts as a link.
(Other definitions for beryl that I've seen before include "Green stone" , "Blue, green or yellow mineral, sometimes a gemstone" , "Emerald or aquamarine" , "Girl's name; gem" , "- - Bainbridge (lit.)" .)
But I've got no explanation for this one! Could you help me understand?
(Other definitions for ruby that I've seen before include "Completely" , "Red precious stone" , "Deep red - transparent gemstone" , "Gemstone - shade of red" , "Fortieth anniversary stone" .)