It is called silt, but really there are a number of SILTS, some almost like clay and some almost like sand; they shade one into the other.
"Lessons on Soil"
E. J. Russell
A glacial stream would be milky blue or milky green from glacial SILTS; and while game seeks the cool heights in summer, the animals prefer the snow-line and avoid the chill of the iced masses in a glacier.
"The Story of the Trapper"
A. C. Laut
The SILTS of glacial rivers are little different from freshly-powdered rock.
"The Birth-Time of the World and Other Scientific Essays"
J. (John) Joly