- GeoRef, Copyright 2004, American Geological Institute. Reference includes data from Bibliography and Index of Geology Exclusive of North America, Geological Society of America, Boulder, CO, United States
Mg-rich cordierite occurs in a cordierite-garnet granulite near Nongriab, Assam, India, in association with garnet identified as almandite with subordinate pyrope, Al 73 Py 20 Sp 2 An 3 Gr 2 . Chemical and optical data are given for the cordierite. Consideration is given to the development of iron-rich garnet in association with Mg-rich cordierite. The data indicate that such garnets have a restricted composition range and that the conclusion which holds that cordierite associated with almandite has a higher FeO/MgO ratio is apparently in error.