Sand grains can be distinguished from silt grain by

#1) Sand grains can be distinguished from silt grain by .
The answer is size. Sand grains are finer than gravel and coarser than silt. Sand is a naturally occurring granular material composed of finely divided rock and mineral particles. Silt is granular material silt particles are larger than clay but smaller than sand particles, whose mineral origin is quartz and feldspar.

The peak above is part of the  sierra madre occidentals ,  a chain of volcanic mountains that runs through the middle of central america.