1. A soft silvery metallic element of the alkali metal group; burns in air and reacts violently in water; occurs in carnallite and lepidolite and pollucite
   "Rubidium is used in atomic clocks";
   - Rb, atomic number 37

Derived forms: rubidiums

Type of: metal, metallic element

Part of: carnallite, lepidolite, pollucite

Encyclopedia: Rubidium