material{   //-----------------------------------------------------------
        texture { pigment{ rgbf <0.98, 0.98, 0.98, 0.9> }
                  finish { diffuse 0.1 reflection 0.2  
                          specular 0.8 roughness 0.0003 phong 1 phong_size 400}
                } // end of texture -------------------------------------------
        interior{ ior 1.5 caustics 0.5
                } // end of interior ------------------------------------------
      } // end of material ----------------------------------------------------