Did box of extra diamonds to be worn by Queen (7)
I believe the answer is:
sparred
'did box' is the definition.
(sparring is a kind of boxing)
'extra diamonds to be worn by queen' is the wordplay.
'extra' becomes 'spare' ('spare' can be a synonym of 'extra'**).
'diamonds' becomes 'd' (abbreviation in bridge say).
'to be worn by' means one lot of letters goes inside another (I've seen this in other clues).
'queen' becomes 'r' (r is abbreviation regina. e.g. in ER ).
'spare'+'d'='spared'
'spared' enclosing 'r' is 'SPARRED'.
'of' acts as a link.
(Other definitions for sparred that I've seen before include "Did train at boxing" , "Fought" , "Boxed; argued" .)