In which country was boron discovered?

Boron was discovered in 1808 in both France and Great Britain. The chemists Joseph-Louis Gay-Lussac and Louis-Jaques Thénard isolated boron in their laboratory in France. Around the same time, Sir Humphry Davy was isolating boron in his lab in London; all three chemists are credited with the discovery.

All three chemists discovered boron by reacting boric acid with another element, possibly magnesium or potassium. Their samples were about 60 percent pure and produced a solid that the French chemists saw as gray and Davy called dark olive. A 99 percent pure boron sample was later isolated in 1909 by Ezekiel Weintraub, an American chemist who used hydrogen to reduce boron halides.