Light material can turn red (6)
I believe the answer is:
tinder
'light material' is the definition.
'tinder' can be an answer for 'material' (I have seen 'Combustible material ' mean 'tinder' so perhaps 'material' could also mean 'tinder'). I am not certain of the 'light' bit.
'can turn red' is the wordplay.
'can' becomes 'tin' (both are metal containers).
'turn' indicates anagramming the letters.
'red' is an anagram of 'der'.
'tin'+'der'='TINDER'
Can you help me to learn more?
(Other definitions for tinder that I've seen before include "Dry material for starting fires" , "It's used to start a fire" , "Dry stuff to light fire with" , "Dry stuff that catches fire easily" , "Dry stuff that fires easily" .)