Small type of green (7)
I believe the answer is:
emerald
This clue could be a double definition.
'small type' is the first definition.
'emerald' can be an answer for 'type' (I've seen this before). I'm not sure about the 'small' bit.
'green' is the second definition.
(emerald is a shade of green)
'of' is the link.
Can you help me to learn more?
(Other definitions for emerald that I've seen before include "...re medal? (Anag)" , "and 1 Across: Ireland" , "Precious green stone" , "Small size of type, in printing" , "Mere lad (anag.)" .)