Along with gallium and mercury, rubidium is one of the three metals that are liquid at room temperature. Rubidium is ranked 16th in abundance in the earth’s crust; however, it is rarely concentrated to levels of interest for commercial extraction.
The principal source of rubidium is from certain highly evolved granitic rocks, where the rubidium typically occurs in potassium feldspars and in lithium micas from which it is extracted commercially. There is a rubidium feldspar, known as ‘rubicline’, which is relatively rare but has been documented in two of Avalon’s projects, Separation Rapids and Lilypad.
Applications of Rubidium:
- Chemicals: Rubidium chloride is used in biochemistry to induce cells to take up DNA, and as a biomarker since it is readily taken up to replace potassium, and does not normally occur in living organisms.
- Ceramics and Specialty Glass: Rubidium feldspar is used in high voltage ceramic insulators.
- Electronic and Electromotive: Rubidium can be used in place of cesium in ion propulsion powered space probes, magnetometers and atomic clocks. Rubidium is also used in opto-electronic devices such as night vision glasses and photoelectric cells.
- Energy: Rubidium can be used for ion propulsion systems in space exploration and for use in a thermoelectric generator using the magneto-hydrodynamic principle for power generation.
- Science and Medical: Naturally occurring isotopes of rubidium decay to produce strontium isotopes and lend to the ability to age date rock strata. Rubidium is also alloyed to make mercury and gold amalgams.
Rubidium metal ignites in the air and reacts violently with water and can cause fires. To ensure both health and safety, and purity, this element must be kept under a dry mineral oil, in a vacuum, or in an in an inert atmosphere.