Possibly making red meal green (7)

I believe the answer is:

emerald

I'm a little stuck... Click here to teach me more about this clue!

'green' is the definition.
(emerald is a shade of green)

'possibly making red meal' is the wordplay.
'red meal' can be anagrammed to 'EMERALD'.
However, I am not sure how this is indicated.

Can you help me to learn more?

(Other definitions for emerald that I've seen before include "city in Oz?" , "Mere lad (anag.)" , "Precious green stone" , "Green - jewel" , "Highly-valued variety of beryl" .)

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.