The stable 6-Lithium Isotope is substance of military interest because it's enrichment is  required for production of thermonuclear weapons of mass destruction.  It's enrichment  for that purpose began in Los Alamos, New Mexico after the Manhattan Project and Hiroshima.  Coincidentally, 6-Lithium enrichment has potential to  improve treatment for mental illness, because the current lithium formulation used as a medication consists primarily of the other stable isotope, 7-lithium. Hence, Los Alamos Therapeutics.

https://www.nature.com/articles/mp201190.epdf?shared_access_token=uyYHzLJvxz-HvHp6ysrlkdRgN0jAjWel9jnR3ZoTv0MjOlOqFxxDdQR31FRa7_BU-uYKuylzyg1spVcFc7WIW0ZjZ3gOCHqfjyGvVTA_0Lm_Nb-fZcXW_tR8ZRBnAEbf

https://patentimages.storage.googleapis.com/31/21/00/42576dab4067ac/US20150342985A1.pdf