Like Cerium, Neodymium (Nd) is a rare earth (Lanthanide) element.
Neodymium is used both to color glass and to remove the green color caused by the iron in many silica sources (sand).
Glass colored with neodymium will often shift colors based on the type of light. In short-wave rich sunlight, the glass can tend to a blue-gray colors. In most artificial light the glass will tend towards shades of deep red. Because of this specific behavior with regard to light wave lengths, neodymium is also used to produce a number of scientific use glasses.
Also, neodymium magnets are among the strongest permanent magnets you can buy. So strong that a 3" diameter x .5" neodymium magnet can lift 200 pounds.
This leads to another use of neodymium for glass artists. If you are currently making your own glass frit using any of the techniques that involve metal-against-glass crushing, neodymium magnets provide an excellent way to remove metal contaminants from the glass. Keeping the magnet in a ziplock bag will make it easy to "clean" the magnet and discard the metal bits.