This snowflake's sparkly clusters are made by dipping shaped pipe cleaners into borax dissolved in boiling water with food coloring. As the water cools, borax forms crystals that cling to pipe cleaners.
Source: Martha Stewart Kids, Volume 6 2002
Twist three 5-inch pieces of pipe cleaner together to form a snowflake, then add a 1 1/2-inch piece to each point. Tie the flake with string to a pencil. Find a big enough jar so the suspended flake won't touch the sides.
Fill with 3 tablespoons borax and 1 drop blue food coloring per 1 cup of boiling water. Hang the snowflake in the jar. Let sit overnight; remove.