I can't remember where I saw it now, but you can actually make your own liquid-sand-style nail polishes by, literally, adding sand. Fine grained sifted sand, naturally, but it does actually work.

http://www.morenailpolish.com/2013/03/money-smart-nail-art-tips-and-tutorials.html

There we go. I suspect it would require a bit of trial and error to get the consistency right, but it's certainly feasible. :)