The primordial beryllium-9 abundance, inferred from observations of metal-poor stars and Big Bang Nucleosynthesis calculations, exhibits unexpectedly low or variable values that are difficult to reconcile with standard Lambda-CDM nucleosynthesis predictions. Beryllium-9 is produced in very small amounts during primordial nucleosynthesis, and its observed abundance appears inconsistent with the abundances of other light elements when fitted within a single baryon density framework, suggesting either systematic errors in stellar abundance measurements, non-standard nuclear physics, or modified early-universe conditions (Cyburt et al. 2016; Fields 2011).