Some potassium minerals (lepidolites, biotites, feldspar, carnallite) contain it, together with caesium.
sˌʌm pətˈæsiəm mˈɪnɚɹəlz lˈɛpɪdˌɑːlaɪts, bˌaɪoʊtˈaɪts, fˈɛldspɑːɹ, kˈɑːɹnɐlˌaɪt kəntˈeɪn ɪt, təɡˌɛðɚ wɪð sˈiːsiəm.