There are 17 'rare earth' minerals. They are actually fairly abundant, but difficult to extract - and when they are mined, they are valuable for their uses in some of the advances which the modern world depends on, including the making of fiber-optic cables, lasers, nuclear reactors, and X-ray machines.
Here are the minerals - and some of their uses
Scandium. Found in aerospace alloys and cars' xenon headlamps
Yttrium. Used in energy-efficient lightbulbs, spark plugs and cancer treatments
Lanthanum. Found in camera lenses, battery electrodes, and catalysts used in oil refineries
Cerium. Used in self-cleaning ovens and industrial polishers
Praseodymium. Used in lasers and cigarette lighters
Neodymium. Used in electric motors for electric cars, hi-tech capacitors
Promethium. Found in luminous paint
Samarium. Used in the control rods of nuclear reactors, lasers and atomic clocks
Europium. Used in fluorescent lamps, MRI scanners
Gadolinium. Found in computer memory chips, steel, X-ray machines
Terbium. Used in sonar systems on navy vessels, fuel cells on hi-tech cars
Dysprosium. Used in hard disk drives and lasers
Holmium. Used in mass spectrometers by hospitals and forensic scientists
Erbium. Used in catalysts for the chemicals industry and in batteries designed to store power for the electrical grid
Thulium. Found in portable X-ray machines and lasers
Ytterbium. Used in stainless steel, thyroid cancer treatment and earthquake monitoring
Lutetium. Used in LED lightbulbs, oil refining and medical PET scans
