But carbon-14 dating wont work on dinosaur bones. The half-life of carbon-14 is only 5,730 years, so carbon-14 dating is only effective on samples that are less than 50,000 years old. To determine the ages of these specimens, scientists need an isotope with a very long half-life.

Do diamonds contain carbon-14?

By the way, carbon-14 represents about 1 atom per billion in organic samples (from which many diamonds derive). A 1-carat diamond weighs 0.2g. Thats around 1E22 atoms of Carbon. If this was a sample of modern, biologically-derived carbon, it would contain around 1E10 atoms of carbon.