We used sawdust, not sand. One of the guys uses it in his dioramas and it looks amazing in photogrpahs so we went for that. The best news is that sawdust can be dyed so you can make it any color you want. If you guys are interested I could make a How-to post about it.On the bad news section: sawdust is extremly light so it can't be used outdoors or inside with a fan on, or near open windows, things like that.