Sort of faith I will take lots of tricks, diamonds mostly (7)
I believe the answer is:
islamic
'sort of faith' is the definition.
(Islam is a religion)
'i will take lots of tricks diamonds mostly' is the wordplay.
'will take' is a charade indicator (letters next to each other).
'lots of tricks' becomes 'slam' (I can't justify this - if you can you should believe this answer much more).
'diamonds' becomes 'ice' (slang term for diamonds).
'mostly' means to remove the last letter (most but not all of the word).
'ice' with its final letter taken away is 'ic'.
'i'+'slam'+'ic'='ISLAMIC'
Can you help me to learn more?
(Other definitions for islamic that I've seen before include "Of the Arabic religion" , "Relating to a particular religion" , "Relating to Muslim religion" , "of faith" , "Relating to Muhammad's religion" .)