To derive is defined as to come from, be created from or be developed out of something else. An example of derive is when you get the idea for a new fund raising event based on the event the previous year.
Rubidium: geological information. Rubidium is far too reactive to be found as the free metal in nature. It is relatively rare, although it is the 16th most abundant element in the earth's crust. Rubidium is present in some minerals found in North America, South Africa, Russia, and Canada. It is found in some potassium minerals (lepidolites, biotites, feldspar, carnallite), sometimes with caesium as well.
Rubidium is pronounced as roo-BID-ee-em. History and Uses: Rubidium was discovered by the German chemists Robert Bunsen and Gustav Kirchhoff in 1861 while analyzing samples of the mineral lepidolite (KLi 2 Al(Al, Si) 3 O 10 (F, OH) 2) with a device called a spectroscope. The sample produced a set of deep red spectral lines they had never seen before.