Can't remember the details, but you can make ornaments using an almost-saturated solution of borax? NaCl? and colored pipe cleaners. Shape the pipe cleaners in ornament-shapes (either actual shapes, or angels, spirals, squiggles, etc.) and suspend them in the hot solution. Crystals will form around the pipe cleaner shapes as the solution cools. We used colored pipe cleaners and they were really pretty!
I bet you can search online or on Pinterest to find the actual salt used and concentrations.