The rare-earth elements (REEs) are a group of 17 elements (atomic numbers 57-71) that exhibit a range of unique electronic, optical and magnetic properties.
Because of their similarities to the REEs, scandium (Sc) and yttrium (Y) are considered by most scientists to be REEs too. Components manufactured from REE-containing compounds can have a profound effect on the ultimate performance of a range of complex, engineered systems and devices. Rare earths are used in the manufacturing of iPods, computers, cell phones, hybrid car motors, wind turbines and high tech military systems work.
A common assumption by many people who are learning about rare earths is to assume that there must be very little of these elements on the planet. In fact, this designation is left over from the early 20th century when it was recognized how difficult it was to separate REEs from other minerals.
Some rare earths are in fact more abundant than other better known elements. For example, there is more of the rare earth element neodymium than there is gold. There are however many economic deposits of gold, but very few of neodymium.
Another mistake is to believe that these elements are created from common earth, when in fact they are classified as metals.