Crossword Genius

Mineral box (4)

Ross

I believe the answer is:

spar

I believe this is a double definition.

'mineral' is the first definition.
(I know that spar is a type of mineral)

'box' is the second definition.
(spar can mean to box)

(Other definitions for spar that I've seen before include "Box; various minerals" , "Stout pole, nautically" , "Act as boxer" , "microcrystalline mineral?" , "Mineral; strong pole" .)

I've seen this clue in The Times.
Want a hint initially instead of a full solution? Install my app