A dark red strand (6)
I believe the answer is:
maroon
I believe this clue is a double definition.
'a dark red' is the first definition.
(I've seen this in another clue)
'strand' is the second definition.
(as in marooning someone on an island)
(Other definitions for maroon that I've seen before include "Isolate uncomfortably" , "Could be a warning signal" , "Strand, isolate" , "Slaves' descendant" , "Dark brownish-red" .)