Translucency or Sub-Surface Scattering could make for an excellent case for softer looks sand grains even when rendered from a distance as light scatters through the grains. When i see sand rendered the shading looks to harsh. The same can be said for stones based on what they are comprised of. Here is what i mean for an up-close photo of sand grains.
You could probably recreate that image with very very small rocks and a tinted water shader :)
So adding a water shader to a fake stones shader, color shader input?
Possibly, try it, I'm in Julia land at the moment :)
I'd go for a very, very small decay distance, 0.1mm>0.01mm
Might take a while to render though :)