Be -Gd- is a chemical element with atomic number 64. Gadolinium is a silvery-white, malleable and ductile rare-earth metal. Gadolinium is found in nature only in combined (salt) form. Gadolinium was first detected spectroscopically in 1880 by Jean-Charles Galissard de Marignac who separated its oxide and is credited with its discovery. It is named for gadolinite, one of the minerals in which it was found, in turn named for geologist Johan Gadolin. The metal was isolated by Lecoq de Boisbaudran in 1886. Gadolinium metal possesses unusual metallurgic properties, with as little as 1% of gadolinium improving the workability and resistance of iron, chromium, and related alloys to high temperatures and oxidation. Gadolinium as a metal or salt has exceptionally high absorption of neutrons and therefore is used for shielding in neutron radiography and in nuclear reactors. Like most rare earths, gadolinium forms trivalent ions which have fluorescent properties. Gadolinium salts have therefore been used as green phosphors in various applications.