How would I go about painting what looks like sand on the bottom of a wall?

I want to have my bathroom with sand on bottom and sky on rest of the wall. How would I go about getting a sand like wall what tools or techniques could I use and what colors would you recommend.How would I go about painting what looks like sand on the bottom of a wall?
I used to ask this type of question , too. Years ago. Then I learned that


the only way to get the effect you want is to understand what you are seeing. Find the thing you want to depict and really study it; what is it you are actually seeing? Whatever you see you can paint.