Five isotopes of zinc are found in nature. Zn is the most common isotope, with 48.63% of naturally occurring Zinc. This isotope has a half-life of 4.3x10 years. This is so long, that its radioactivity can be ignored. Similarly, (0.6%), with a half life of 1.3x10 years is usually considered to not be radioactive. The other isotopes found in nature are (28%), (4%) and (19%).