Lutetium is a chemical element with the symbol Lu and atomic number 71. It belongs to the group of elements known as the lanthanides, which are found in the f-block of the periodic table. Lutetium is a silvery-white metal that is relatively hard and dense. It is primarily used in various applications, including catalysts in petroleum refining and in certain types of phosphors for lighting and display technologies. Lutetium is one of the rarest elements in the Earth's crust, making up only about 0.0005% of it. It was discovered in 1907 by Georges Urbain, Carl Auer von Welsbach, and Charles James independently. Due to its scarcity and unique properties, lutetium is often used in