C-14 is everywhere it shouldn't be. Unless from a secondary source, like contamination or neutron capture, anything millions of years old should have NO Carbon-14.
However diamonds are virtually impervious to contamination, and the world's vast fossil fuel deposits are not radioactive. Therefore neutron capture and contamination cannot explain the significant quantities of radiocarbon in such specimens.
Scientists consistently find C-14, as reported in 2011 in the journal PLoS One of an allegedly 80-million year old mosasaur(soft tisse as well), and as reported elsewhere in natural gas, limestone, fossil wood, coal, oil, graphite,marble, ten dinosaurs, and even in supposedly billion-year-old diamonds.