Mineral one removed from green box (8)
I believe the answer is:
feldspar
'mineral' is the definition.
(feldspar is a kind of mineral)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for feldspar that I've seen before include "Large wading bird" , "Mineral; red flaps (anag.)" , "Abundant mineral" , "Common mineral" , "crystal" .)