The Natural and amazing Blue Color of the Rio Celeste is due to the mixing of 2 rivers. The acidity of the water of the River Buenavista changes the size of the suspended silica colloids of the River Quebrada Agria and make them blue due as them become the Rio Celeste. The Blue color is due to an Optical Effect similar to a Rainbow which would shows only the blue color instead of the 7 colors.