I guess my question would by why? Why would you want to deviate from commonalities?
I think I've read here and there that it can be done, but that doesn't make it a good idea. At best, your sand bed will be unpredictable.
Silica sand will limit your options somewhat. I've heard that it is "sharp", so I don't think sand sifters will like it very much. If it's as fine as you describe, you may have issues with powerheads blowing it around?
At the end of the day, there are lots of people using it without major issues, but it's not for me.
Google is your friend...
http://www.reefs.org/library/article/r_toonen9.html