Gem pedlar emerging from behind pockets (7)
I believe the answer is:
emerald
'gem' is the definition.
(type of gem stone)
'pedlar emerging from behind pockets' is the wordplay.
'pockets' indicates the answer is hidden within the clue (pocket can mean to contain).
'from behind' says the letters should be written in reverse.
'dlareme' can be found hidden inside 'pedlar emerging'.
'dlareme' in reverse letter order is 'EMERALD'.
(Other definitions for emerald that I've seen before include "Ireland is often called The .......Isle" , "Bright green colour" , "city in Oz?" , "and 1 Across: Ireland" , "Green - jewel" .)