Shiny gray metal which quickly oxidizes on exposure to atmospheric gases m.p. 180.54 ºC; 356.97 ºF b.p. 1347 ºC; 2457 ºF density 0.534 g/cc; 33.337 pound/cubic foot	memory peg
	1817 Johan August Arfwedson, Sweden
	λιθος (lithos) = stone, rock (Greek) Named by Jakob Berzelius

Johan August Arfwedson (also Arfvedson, 1792-1841), a student of Jakob Berzelius, analyzed in 1817 the mineral petalite (LiAlSi₄O₁₀), discovered in a rock by the Brazilian José Bonifácio de Andrada e Silva (1763-1838). This rock was found on the island of Utö, outside Stockholm in Sweden. In 1800 Andrada described the minerals petalite and spodumene in this rock.

Several chemists had previously failed to investigate the red color petalite imparted to flames, or the puzzling losses during its analysis. Arfwedson found the rock was roughly 80% silica, 17% alumina, and 3% alkali. He found the alkali did not precipitate in tartaric acid like Potassium and was not Magnesium. Calculating its composition by presuming it to be soda resulted in a 5% excess. Two careful repetitions convinced Arfwedson that it was a new element which has a greater capacity to react than the other alkalies. Berzelius wrote to the French chemist, Comte Claude Louis Berthollet (1749-1822) about this discovery and the naming, this letter was copied in Gilbert's Annalen of 1818:

"We named this alkali «Lithion», this name recalls that it was discovered in the mineral kingdom, whereas the two others have their origin in the vegetable kingdom. In the french nomenclature it will probably be named «Lithine», and in English «Lithina» in analogy with the names of the other alkalis in these languages."
Gilbert adds in a note almost a whole paper on the German name, the grammatical gender etc. In this note, he mentions also the name Lithium for the metal in the alkali Lithon.

The name is derived from the Greek λιθος [lithos] = stone, rock. This name was given because it was discovered from a mineral source whereas the other two common Group 1 elements, Sodium and Potassium, were discovered from plant sources.

← Petalite. A rare large piece, 15 x 7 cms and 630 grams.
Courtesy of Arnaud Demerson, Minéraux et Fossiles, Carry le Rouet, France

• Mary Elvira Weeks, Discovery of the Elements, comp. rev. by Heny M. Leicester (Easton, Pa.: Journal of Chemical Education, 1968), pp. 457-471.