From what I can tell it's mostly used for drilling. See, e.g., https://en.wikipedia.org/wiki/Barium_sulfate https://en.wikipedia.org/wiki/Barium_sulfate and htt

From what I can tell it's mostly used for drilling. See, e.g., https://en.wikipedia.org/wiki/Barium_sulfate https://en.wikipedia.org/wiki/Barium_sulfate and https://www.acs.org/content/acs/en/molecule-of-the-week/archive/b/barium-sulfate.html https://www.acs.org/content/acs/en/molecule-of-the-week/arch...