Chocolatier dismisses other whitish type of material (6)
I believe the answer is:
Here is my best explanation:
'material' is the definition.
(calico is a kind of material)
I don't understand the rest of the clue.
(Other definitions for calico that I've seen before include "Cotton cloth or fabric", "Unbleached cotton cloth", "White cotton fabric", "Plain cotton cloth, white or unbleached", "Coarse cloth with a bright print", "spotted in America", "Coarse printed cotton cloth", "Given material for dress", "Type of cotton cloth" and "Unbleached sixteen down cloth".)