British rely on reshaping stone (5)
I believe the answer is:
beryl
'stone' is the definition.
(I've seen this before)
'british rely on reshaping' is the wordplay.
'british' becomes 'b' (abbreviation e.g. in 'BBC').
'on' says to put letters next to each other.
'reshaping' indicates anagramming the letters (I've seen 'reshaped' mean this).
'b' put after 'rely' is 'relyb'.
'relyb' is an anagram of 'BERYL'.
(Other definitions for beryl that I've seen before include "Girl's name - gemstone" , "Green stone" , "Girl's name - jewel" , "Coloured stone" , "Pale greenish" .)