Desert sand (6)
I believe the answer is:
strand
This clue might be a double definition.
'desert' is the first definition.
(I know that strand is a more specific form of the action desert)
'sand' is the second definition.
The answer and definition can be both substances as well as being singular nouns.
Maybe there's a link between them I don't understand?
Can you help me to learn more?
(Other definitions for strand that I've seen before include "Beach - desert" , "Thread; leave in lurch" , "Scottish gutter" , "Run aground, beach" , "Maroon - bit of hair" .)