What is allanita?

Allanite is a rare earth mineral that is primarily composed of calcium, aluminum, iron, silicon, oxygen, and a number of rare earth elements such as cerium, yttrium, and gadolinium. It was first discovered in the early 19th century in southern Norway and has since been found in a number of locations around the world. Allanite is often used in the ceramic industry as a source of rare earth elements, and it is also sometimes used as a gemstone due to its attractive brown to black color and unique crystal structure. Allanite is a relatively hard mineral, with a Mohs hardness of around 5.5 to 6, and it typically occurs in granite and other igneous rocks. Its name is derived from the Scottish mineralogist Thomas Allan, who first identified the mineral in the 19th century.