Elementymology & Elements Multidict

memory peg	Very soft, very reflective metal which holds its shine. (Can be cut with a knife) melting point 157 °C; 314 °F boiling point 2080 °C; 3776 °F density 7.31 g/cc; 456.35 pounds/cubic foot
1863 Ferdinand Reich and Hieronymus Theodor Richter, Germany
named after the indigo blue spectral stripe

Indium was discovered in 1863, by the physics professor Ferdinand Reich (1799-1882) and his assistant Hieronymus Theodor Richter (1824-1898) at the Freiburg School of Mines (note), while they were checking sphalerite, a sulphide ore of Zinc, with a spectrograph looking for Thallium (which was discovered in 1861). Reich, who was colourblind, was assisted by Richter for the spectral analysis. After several attempts, Reich obtained a precipitate that he knew to be a sulfide of an unknown element. He then used several spectrographic techniques to identify the new element.

Richter observed a bright blue stripe, unknown in any other spectrum and distinct from the blue stripe of Cesium. To this new element was given the name Indium because of the bright indigo blue spectral stripe. The pigment indigo, earlier indico, comes from Latin indicum, the Indian substance or dye. The Sanskrite name was nih, from nila, dark blue, and this through Arabic al-nil, annil, gives "aniline".

Native indium is extremely rare under natural conditions and only of scientific interest. Metallic indium was first obtained in 1867 by T. Richter.

Chemistianity 1873 NTYAN INDIUM, a cousin german to Zinc, Is a soft, white, highly lustrous metal, Like Platinum in colour. 'Tis ductile, And will mark paper or receive a polish. J. Carrington Sellars, Chemistianity, 1873, p. 138

• Mary Elvira Weeks, Discovery of the Elements, comp. rev. by Henry M. Leicester (Easton, Pa.: Journal of Chemical Education, 1968), pp. 613-620.