abstract:Rubidium (Rb) has 32 isotopes, with naturally occurring rubidium being composed of just two isotopes; 85Rb (72.2%) and the radioactive 87Rb (27.
The measurementof the decayofradioactiveisotopes, especiallyuranium, strontium, rubidium, argonandcarbon, has allowedgeologists to morepreciselydetermine the ageof rock formations.