I beleive the ADA seriu stones or whatever their called are a type of marble. In Alabama there's a "marble belt" along the Coosa river which is pretty close to my house. Maybe google something like this is your area? That's how we found out about it. You could also try a local landscaping place and see if they have any marble. If you're near Birmingham or Sylacauga Alabama I could tell you where to find some nice marble stones. You're best bet is prob. an upscale landscaping place though.