The girl from Redstone (4)
I believe the answer is:
ruby
'the girl' is the definition.
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for ruby that I've seen before include "Gemstone comprising mainly aluminium oxide" , "A red jewel" , "Completely" , "Gemstone - shade of red" , "Stony girl" .)