Would you like a receipt? medical research charities group Ytterbium, with the symbol Yb and an atomic number of 70, is a rare earth metal that is soft, malleable, and ductile. It is usually found with other rare earth elements and is most often recovered commercially from monazite sand. It was discovered by Swiss chemist Jean Charles Galissard de Marignac in 1878 and named after the Swedish village Ytterby located near the spot where he found the new mineral. It was not until 1953, however, that scientists precisely determined Ytterbiumâs chemical properties.