Europium

In nature, europium is found in the Earth's crust, 1.06-2.1 ppm, in minerals such as monazite, bastnaesite and gadolinite, of which the first two are the commercial sources [4]. Also detected spectroscopically in the Sun and some distant stars [4]. The isotopes found in nature are ¹⁵¹Eu (47.8 %, stable) and ¹⁵³Eu (52.2 %, stable) [4].