The primordial abundance of Beryllium has not been observed. The production in SBBN is 9Be / H < 10-17 , , orders of magnitude below the observed level. Inhomogeneous BBN allows much higher abundances, possibly approaching detection .
Be is observed. It is created in the ISM when cosmic rays strike C, N and O nuclei, and it is destroyed in stars. It is difficult to use Be to constrain the cosmic ray production of Li because the production ratio is highly model dependent . Beryllium is observed in the atmospheres of halo stars, including those on the Spite plateau. Boesgaard et al.  have found that Be increases with Iron, and that Be increases 8 times faster than Oxygen, a rate consistent with cosmic ray creation. There is some evidence for a spread in Be as a given Fe/H, but no sign of a primordial plateau, down to Be/H = 10-13.5.