It's Elemental

The mineral gadolinite ((Ce, La, Nd, Y)₂FeBe₂Si₂O₁₀), discovered in a quarry near the town of Ytterby, Sweden, has been the source of a great number of rare earth elements. In 1843, Carl Gustaf Mosander, a Swedish chemist, was able to separate gadolinite into three materials, which he named yttria, erbia and terbia. As might be expected considering the similarities between their names and properties, scientists soon confused erbia and terbia and, by 1877, had reversed their names. What Mosander called erbia is now called terbia and visa versa. In 1878 Jean Charles Galissard de Marignac, a Swiss chemist, discovered that erbia was itself composed of two components. One component was named ytterbia by Marignac while the other component retained the name erbia.

Marignac believed that ytterbia was a compound of a new element, which he named ytterbium. Other chemists produced and experimented with ytterbium in an attempt to determine some of it's properties. Unfortunately, different scientists obtained different results from the same experiments. While some scientists believed that these inconsistent results were caused by poor procedures or faulty equipment, Georges Urbain, a French chemist, believed that ytterbium wasn't an element at all, but a mixture of two elements. In 1907, Urbain was able to separate ytterbium into two elements. Urbain named one of the elements neoytterbium (new ytterbium) and the other element lutecium. Carl Auer von Welsbach, an Austrian chemist working independently of Urbain, reached the same conclusions at nearly the same time. Welsbach chose the names albebaranium and cassiopium for these elements. Urbain was eventually credited with the discovery of the elements and won the right to name them, although chemists later changed the name neoytterbium back to ytterbium and changed the spelling of lutecium to lutetium. Today, lutetium is primarily obtained through an ion exchange process from monazite sand ((Ce, La, Th, Nd, Y)PO₄), a material rich in rare earth elements.

Lutetium is one of the most difficult elements to prepare and has no large scale practical uses, although some of its radioactive isotopes can be used as a catalyst in the cracking of petroleum products and a catalyst in some hydrogenation and polymerization processes.