Hazenite is a hydrous phosphate mineral with chemical formula of KNaMg2(PO4)2 · 14 H2O, therefore a hydrous alkali magnesium phosphate. It is a member of the struvite group. It was first described for an occurrence adjacent to Mono Lake, California, and named after Robert M. Hazen of the Carnegie Institute. It was approved as a new mineral on February 28, 2008 by the Commission on New Minerals of the International Mineralogical Association.