Primordial technetium

In 1956 Boyd and Larson thoroughly sought for technetium in various samples using analytical methods of high sensitivity such as neutron activation, mass spectrometry, emission spectroscopy, spectrophotometry, and polarography. Not one of their numerous concentrates revealed traces of natural technetium. It now seems clear that primordial technetium does not exist in nature. 

While there are over 30 known isotopes of technetium, the most stable exhibit half-lives on the order of only 10 years. Since the age of the earth is of the order of lOP years, all primordial technetium has long since decayed. Traces of Tc are formed naturally by the spontaneous fission of Kenna and Kuroda isolated about one nanogram of Tc from 5.3 kg of pitchblende [12]. 

---