Another source I use is Silica sand for fish tank filters, or Chinchilla Dust (sold at pet stores - Pets at home price £5.50 for 3Kg). I add some black acrylic paint to the PVA/Water mix to give a bit of shadow detail between the grains. For the nuts, as per your previous video's on making flock, adding a spot of acrylic paint the final blitz will give a stain to the nuts. Great video Gormo. Paul