Silicate spinels are important minerals in the transition zone region of the Earth and in order to understand seismic signals from these depths (550-660 km) we need to know the elastic properties of these minerals. disorder between the 2+ metal and 4+silicon sites is predicted to be significant and to have a large effect on the seismic velocities but the amount of disorder has never been experimentally measured. We will use neutron diffraction, which is the ideal method to look at the positions of the metal and silicon ions in the structure to directly measure the amount of disorder under conditions of high pressure the temperatures of the Erath's transition zone.