Stone working with axes (4)
I believe the answer is:
onyx
'stone' is the definition.
(type of gemstone)
'working with axes' is the wordplay.
'working' becomes 'on' (on can mean working or activated).
'with' says to put letters next to each other.
'axes' becomes 'yx' (Y axis and X axis).
'on'+'yx'='ONYX'
(Other definitions for onyx that I've seen before include "Sort of agate" , "material for making cameos" , "Smooth stone with bands of colour" , "Variety of agate, used as a gemstone" , "Black and white striped gemstone" .)