Originally Posted by Mudball
Looks like some great help your getting there bcs19. Not to take away from Brad giving his own answer but I would like to believe that he was referring to "aggregate" (gravel) that would be in 3/4" in size and/or smaller for drainage purposes.
I'd agree.... He's probably talking about what is generally refered to as #6 Stone -
This is classified as a coarse aggregate meeting ASTM C 33, Size No. 67. It is light in color, a blend of beige, tan, white, gray and small amounts of black and red stones. It is crushed, washed and screened to a size less than 3/4" with no fines........... although there are cheaper runs of the same size gravel you can buy.
There are also much more expensive glass stones you can purchase. These come in all colors, and give a beautiful reflection to a firepit. The effect is really startling.