you are welcome AND WELCOME TO THE FORUMS!
i've purchased it a garden supply shops.
even the 'expanded stuff' is dusty when opened, poured and handled.
but once it's poured into the pit, it settles, and the 1/4 inch (rice sized) bits are near the surface.
might wanna just buy a bag of whatever and try it....
basically this is just a light pile of stuff the gas percolates up through to flame on the surface.
the company that makes the 'dancer may also sell replacement bags of 'the good stuff!'
http://www.hillydidit.com/faq.asp
the advantage over lava stones is NO HEAT retention in the fluff which would be a worry 4 me in these things.
cheers
2air'