Castle material (4)
I believe the answer is:
sand
(Other definitions for sand that I've seen before include "Rock particles; smooth" , "Egg timer grains" , "Content of hourglass" , "Very tiny grains of rock" , "woman writer Chopin loved" .)
I believe the answer is:
sand
(Other definitions for sand that I've seen before include "Rock particles; smooth" , "Egg timer grains" , "Content of hourglass" , "Very tiny grains of rock" , "woman writer Chopin loved" .)