W. Noddack, Ida Tacke, and O. Berg in Berlin, Germany.
Remarks
Very soft metal with silvery white luster
when cut. Ignites in air and reacts violently with water. Finds little use
outside research. Minerals with a high Rb content are use for age-dating
by the Rb-Sr isotope method. Most minerals containing potassium (K) also
contain Rb in trace amounts.
Diagnostic tests:
In solution, rubidium will give a flame test color of a nice red. This flame test will be contaminated with the colors of the
other alkaline elements which are present in the sample (in particular the
red color from calcium). You will probably
need a diffraction spectroscope to view the red emission lines from
rubidium.
References
Emsley, J., 1991; THE ELEMENTS : Sec. Ed.,
Clarendon Press, Oxford, 251 p.
(* - Mineral Name Is Not IMA Approved)
(! - New Dana classification added or changed from Danas New Mineralogy)
(? - IMA Discredited Mineral Species Name)
There are 11 minerals with Rb in the Mineralogy Database.