Knitted or woven material with a diamond-shaped pattern of two or more colours (6)
I believe the answer is:
argyle
(Other definitions for argyle that I've seen before include "Knitted or woven with diamond-shaped pattern" , "Sock pattern" , "Lozenge pattern (socks)" , "Old Scottish county; part name of a W Country football team" , "Lozenge-shaped design" .)