One of the RAREST elements with a cool property!

[00:00:00]This is a natural lutetium in its metallic form. It reacts in oxygen to form its oxide, and that's why I store it in an ampule to preserve its metallic luster. Lutetium is among the very few elements that has a naturally occurring radioactive isotope that has all the sweet nuclear properties to be easily measured with the Radiocode 110. The isotope can be quite quickly identified in the spectrum. It's lutetium 176. With 2.6% it's quite abundant, and as we can see it has two easily recognizable gamma lines. But the fun thing about lutetium 176 is, of course, it's long-lived.

[00:00:37]Otherwise, we wouldn't have it in natural lutetium. But for the longest time, we still didn't accurately know its half-life. Even until 2022, its half-life was only known with an uncertainty of plus or minus 350 million years, which is insane given that its half-life is roughly 38 billion years.

[00:00:56]And by today's knowledge in 2026, its half-life is exactly 37.19 billion years plus or minus 70 million years, which is a lot more accurate than before.