Delivered price of Green Diamond synthetic olivine is very dependent on freight and packaging. Even if the delivered cost is more, you will see savings in reduced makeup sand, lower pouring temperatures, and better finish, which should negate any higher price. Also, since Green Diamond sand is 10-20% lighter in bulk density, there would be savings in disposal if you pay by the ton and there are more cubic feet of Green Diamond sand per ton than Olivine or Silica.