It has been calculated that there are at most 30 grams of francium in the earth's crust at any time, due to its extremely short half-life of 22 minutes.
ɪt hˈæzbiːn kˈælkjʊlˌeɪɾᵻd ðæt ðɛɹˌɑːɹ æt mˈoʊst θˈɜːɾi ɡɹˈæmz ʌv fɹˈænsiəm ɪnðɪ ˈɜːθz kɹˈʌst æɾ ˌɛni tˈaɪm, dˈuː tʊ ɪts ɛkstɹˈiːmli ʃˈɔːɹt hˈæflˈaɪf ʌv twˈɛnti tˈuː mˈɪnɪts.