Gray-white metal m.p. 1313±1 ºC; 2395±1.8 ºF b.p. 3266 ºC; 5911 ºF density 7.9004 g/cc (25 ºC); 493.2059 pound/cubic foot (77 ºF)	memory peg
	1880 Jean Charles Galissard de Marignac, France
	gadolinite, mineral named after Johan Gadolin

The story of discovery and naming of this element began with Carl Gustav Mosander splitting old yttria into three new earths, yttria proper, erbia, and terbia (see table to the right, and Yttrium). Mosander's erbia was confirmed by Marc Delafontaine in 1878 and renamed terbia, since the name erbia was since 1860 in use for Mosander's Terbium.

Delafontaine's terbia was split by Jean de Marignac in 1880 into an earth to which he gave the provisial name Yα and true terbia (note).

In 1886 François Lecoq de Boisbaudran produced a more pure form of the earth Yα. He separated it from Mosander's didymia, which originated from the mineral samarskite (cf. Samarium). After a correspondece with Marignac, Lecoq announced the Academie that Marignac had chosen to give Yα the name gadolinia. (note). The reason is not given, but clearly is it named after the mineral gadolinite:

Gadolinite is named after Johan Gadolin (1760-1852), the second holder of the first chair of chemistry in Finland. After the old Royal Academy of Åbo was moved to Helsinki in 1828, this chair became the Chair of Organic Chemistry at the University of Helsinki (note).

In a mineral from the Ytterby quarry near Stockholm he discovered in 1794 the element Yttrium (which he named Ytterbium). Yttrium was the first of the so-called rare-earth elements discovered. During the following 90 years a number of new rare-earths elements were discovered, some real, some alleged (for the whole story, start with Yttrium or Cerium).

The history of the surname is amusing: When the son of a Finnish farm 'Maunula' near Turku entered the learned path, he needed a surname and re-latinized (Maunu = Magnus) his farm name to "Magnulin". Later the versions Megalin, Isolin and Gadolin, from Greek, Finnish and Hebrew, respectively, were considered in the family, and the last one was adopted.

Thus Gadolinium has the distinction of being the only elemental name derived from Hebrew (gadol = "great").

See also: Chronological list of discovery of the rare earths, their names in different languages etc. on the Yttrium page

Further reading:

• Mary Elvira Weeks, Discovery of the Elements, comp. rev. by Heny M. Leicester (Easton, Pa.: Journal of Chemical Education, 1968), pp. 667-699.
• Seltene Erden. Gmelins Handbuch der anorganische Chemie, 8. Aufl.; System-Nummer 39 (1938).
• P. Pyykkö and O. Orama, "What did Johan Gadolin actually do?", C. H. Evans (ed.), Episodes from the History of the Rare-Earth Elements, Kluwer, Dordrecht (1996), pp. 1-12. Thanks to professor Pekka Pyykkö, Professor of Chemistry, University of Helsinki, for his help.
• Peter B. Dean, and Kirsti I. Dean, "Sir Johan Gadolin of Turku: The Grandfather of Gadolinium." (on-line PDF file).