Be in commercial beryllium

¹⁰Be has been observed at a level of about 10⁻¹⁴ in four commercially available beryllium compounds. The possibility that this ¹⁰Be arises from cross-talk in the ion source has been eliminated. On the other hand, beryllium oxide extracted from beryl crystals found at a depth of 30–40 feet in a lithium mine in South Dakota shows no indication of containing ¹⁰Be. An upper limit on its ¹⁰Be:⁹Be ratio is 1.7 × 10⁻¹⁵ at the 95% confidence level.