The magnet in headphones is typically composed of ferrite or neodymium. Magnetic brakes are made up of one or two rows of neodymium magnets. The system is also lighter because the use of high grade neodymium magnets. Hitachi has held more than 600 patents covering neodymium magnets. The strength of neodymium magnets is the result of several factors. They have a neodymium or other rare-earth permanent magnet. The metals that can be extracted from it include&colon; cerium, lanthanum, neodymium, and europium. The video also highlighted the magnetic fields created by the neodymium magnet. Many lanthanides are known for their magnetic properties, such as neodymium. It is the most common of the lanthanides, followed by neodymium, lanthanum, and praseodymium. Metallic neodymium has a bright, silvery metallic luster. Lindsay Chemical Division was the first to commercialize large-scale ion-exchange purification of neodymium. In particular, this would require an greater supply of the rare earth metal neodymium. As with neodymium glasses, such minerals change their colors under the differing lighting conditions. Double nitrate crystallization was the means of commercial neodymium purification until the 1950s.