Sometimes the composition of the original mixture will give a clue , if one finds only one product - a single powder pattern - or if one was trying to make a phase of a certain composition by analogy to known materials but this is rare .
Sometimes the composition of the original mixture will give a clue , if one finds only one product ( a single powder pattern ) or if one was trying to make a phase of a certain composition by analogy to known materials . But this is rare .