Cesium is the 40th most abundant element of the periodic system.
The commercially most important cesium-bearing ore is pollucite, a cesium-aluminum silicate with the chemical formula (Cs,Na)2Al2Si4O12.(H2O).
This ore was formed a long time ago, when the earth's surface was much hotter than it is today, and molten silicates solidified to form huge granite bodies. During solidification, some chemical elements, including cesium, were concentrated in the last fractions to freeze and crystallize as separate minerals.
Pollucite is mined in Canada, Africa, and at other locations throughout the world, from where it is shipped to Albemarle's factory in Langelsheim, Germany. Here, it is processed into a full range of cesium-containing products.
Although cesium has a large number of isotopes, naturally occurring cesium consist exclusively of the nonradioactive isotope 133cesium.