Stained odd building material (4)
I believe the answer is:
sand
'material' is the definition.
(sand is a kind of material)
'stained odd' is the wordplay.
'odd' means one should take alternating letters.
The alternate letters of 'stained' are 'SAND'.
'building' is the link.
(Other definitions for sand that I've seen before include "It's used in glass-making" , "Desert grit" , "Granulated quartz" , "Grains of quartz" , "Shore grain" .)