Cobalt canyon in the side of a mountain. The firm Calera Mining Company started production at the site. The stable form of cobalt is produced in supernovas through the r-process. It comprises 0.0029% of the Earth's crust. Free cobalt (the native metal) is not found on Earth because of the oxygen in the atmosphere and the chlorine in the ocean. Both are abundant enough in the upper layers of the Earth's crust to prevent native metal cobalt from forming. Except as recently delivered in meteoric iron, pure cobalt in native metal form is unknown on Earth. The element has a medium
Isotopes of cobalt Isotopes of cobalt Naturally occurring cobalt (Co) is composed of 1 stable isotope, Co. 28 radioisotopes have been characterized with the most stable being Co with a half-life of 5.2714 years, Co with a half-life of 271.8 days, Co with a half-life of 77.27 days, and Co with a half-life of 70.86 days. All of the remaining radioactive isotopes have half-lives that are less than 18 hours and the majority of these have half-lives that are less than 1 second. This element also has 11 meta states, all of which have half-lives less than 15 minutes. The isotopes of cobalt