Carbon 14 dating diamonds
(3) There's flexible and even transparent blood vessels, cells, and even and hadrosaur DNA (with a half-life of ~521 years) in dinosaur soft tissue fossils.Many such lines of evidence (multiplying as at youngearth.com) undermine the claim by old-earth geologists that the plentiful 14c in "ancient" specimens must come from contamination or neutron capture (see below), and this evidence helps to confirm the young earth interpretation of the data below.
Small amounts of carbon-14 are not easily detected by typical Geiger–Müller (G-M) detectors; it is estimated that G-M detectors will not normally detect contamination of less than about 100,000 disintegrations per minute (0.05 µCi).
Carbon-14 was discovered on February 27, 1940, by Martin Kamen and Sam Ruben at the University of California Radiation Laboratory in Berkeley, California.
Its existence had been suggested by Franz Kurie in 1934. The primary natural source of carbon-14 on Earth is cosmic ray action on nitrogen in the atmosphere, and it is therefore a cosmogenic nuclide.
Most diamonds are really old, and the half-life of 14C is around 5500 years.
So if the diamond is older than say 55,000 years (which is really young as diamonds go), there would be 1/2^10 = 0.098% of the original 14C contained in the diamond. If this was a sample of modern, biologically-derived carbon, it would contain around 1E10 atoms of carbon.