Polybasite is not a common mineral. In Europe, well-formed micro hexagonal crystals come from the Clara Mine, Rankach valley, Oberwolfach, Baden-Württemberg, Germany. Small flaky crystals have come from the Příbram area, Bohemia, Czech Republic. In Peru, Polybasite occurs with
Pyrargyrite at the Uchucchacua Mine, Oyon Province, Lima Department.
Mexico contains several notable localities for this mineral. Large, well-formed crystals of Polybasite have come from the San Juan de Rayas Mine, Guanajuato; and large single crystals and groups from the Chispas Mine, Arizpe, Sonora. Crystal clusters with
Calcite have come from the Proano Mine, Fresnillo, Zacatecas.
Polybasite is very rare in U.S.: Crudely formed crystal clusters have come from the Eagle Mine, Gilman, Eagle Co., Colorado. In Canada, exceptional, well-formed,
iridescent crystals came from a small find Husky Mine, Elsa, Galena Hill, Mayo Mining District, Yukon Territory. Small crystals and flakes come from Cobalt, Timiskaming District, Ontario.