In 1911 Urbain and in 1922 Dauviller thought they had found a new element similar to the rare earths. Urbain called it celtium in honor of his country, France. In spite of this, the definite discovery and the determination of its properties and behavior was only accomplished in 1923 by Coster and Hevesy. The research of these scientists revealed amounts up to 30% of oxide of this new element in zirconium minerals. The discovery was made through spectroscopic techniques using zircon of Norway. Its X ray spectrum revealed the presence of the element 72, filling up the hole in the periodic table predicted by Bohr and Moseley. They named if hafnium after the Latin hafnia the word for Copenhagen.