Rubidium

Rubidium was discovered in 1861 by Robert Bunsen (yes, the Bunsen burner guy) and Gustav Kirchhoff using a brand-new technique called spectroscopy — they identified it by the beautiful deep red spectral lines it produced. The name comes from the Latin 'rubidus,' meaning dark red. Rubidium is a soft, silvery metal that is so reactive it must be stored in sealed glass tubes under an inert atmosphere.

Rubidium ignites spontaneously in air and reacts violently with water. Despite its reactivity, rubidium has important uses. Rubidium atomic clocks are used in GPS satellites — without their incredible precision, your phone's GPS could be off by miles. Rubidium is also used in medical imaging and in special glass for fiber optic telecommunications.

Rubidium's symbol 'Rb' is a unique two-letter element in Spellement. While 'rb' is not common at word beginnings in English, partial emphasis allows spellers to use either 'r' or 'b' individually, adding creative options for element-based word construction.