Hi Cheryl - You got it right - crushed granite. This one in particular is 3/4" clean which I prefer for relatively level gravel driveways over a minus gravel. I guess its depends if you ask the owner or the dog :-) My dog will walk on the 3/4" size gravel but I suspect it might not be the best feeling on his pads based on how he walks (gingerly). A smaller size might be more paw friendly. However the 3/4" size is good for people to walk on as it does get firm over time. Any smaller tends to move around too much. One thing though - my dog does like to dig in the gravel...