1. A method of indexing powder diffraction data, comprising: choosing a maximum impurity peak tolerance level to limit the search for indexing solutions to those where the number of unindexed peaks lies within the tolerance level; choosing a range for the number of calculated peaks to limit the search for indexing solutions to those where the number of calculated peaks falls within the chosen range; selecting a crystal system to search; selecting a powder extinction class to search for indexing solutions; and performing a unit cell search of the selected powder extinction class using a successive dichotomy approach to determine a set of indexing results.