SILTSTONE
Siltstone is a siliciclastic sedimentary rock composed of silt-sized
grains (between 0.0625 mm and 0.00390625 mm in size; i.e., 1/16 mm to 1/256 mm
in size). These feel barely rough to the touch, whereas sandstones feel
fairly rough & gritty. Siltstones are often quartzose in composition,
and they vary in color from black to gray to brown to reddish.
Siltstone