What is the modern hardware/supermarket term for 'laundry bluing'? I want to make this amazing paper Crystal Tree with my kids. One of the ingredients is laundry bluing. It is described thus:


  The magic crystals that are left behind are a combination of the Mrs. Stewart’s Bluing and the table salt. The solution that you created is supersaturated by the bluing and salt that you add to the water. The bluing is a colloid, with many tiny particles suspending themselves within the water. It’s just like when you shake up a snow globe, except the particles of bluing are much smaller than the snow. As the bluing and salt water make their way up the tree, the water begins evaporating. These means there is less water able to support the bluing particles and dissolved salt. This evaporation allows the salt and bluing particles to crystallize, resulting in your beautiful tree.


No one in my supermarket has heard of laundry bluing. Is it possible it is hazardous and has been banned in some states/countries? Perhaps it has another name? Perhaps this has a chemical name?

My question is: What is the modern hardware store/supermarket term for 'laundry bluing'?
The active ingredient is prussian blue which you can make yourself from potassium ferrocyanide and an Fe(III) salt.