SignedLabel on base: UNIVERSITY OF CALIFORNIA CHEMICAL LABORATORY
InscribedLabel on base: UNIVERSITY OF CALIFORNIA / CHEMICAL LABORATORY / Rb2SO4 /Rubidium Sulfate / Prepared by de Haen ; loose paper label probably written in Dr. Richards' handwriting: Dimorphism. These two substances have exactly the same chemical composition, but very different crystographic and other physical properties.
FunctionSet of two samples of rubidium sulphate (objects 3966 and 3967) stored in identical containers. Used to show chemical dimorphism, the ability of a substance to crystallize in two different forms.