Yttrium is almost always found in combination with lanthanide elements in rare earths minerals, and is never found in nature as a free element. Yttrium oxide (Yttrialite-(Y)) also occurs in tungsten particles.
Yttrium oxide is used in ceramics for crucibles for molten reactive metals, in florescent phosphors for lamps, LEDs, computer displays and automotive fuel sensors.
Yttrium oxide stabilized zirconia is used in high temperature applications (semiconductor) and as an electrolyte in fuel cells. It is also used in solid-state lasers.
Yttrium compounds are used as host lattices for doping with different lanthanide cations to produce the red and the green color with Eu3+ and Tb3+ respectively.
Yttrium is used in the production of a large variety of synthetic garnets which are used as microwave filters, gemstones, high power lasers used for precision cutting, welding, etching, boring and targeting.
Yttrium is used to provide a high temperature corrosion resistance in cutting tools.
Other uses include solid electrolytes, electrodes on high-performance spark plugs, catalysts, in aluminum and magnesium alloys, deoxidizer of non-ferrous metals and as a replacement for thorium in gas mantles for propane lanterns.
Owing to its high melting point, its shock resistance and low thermal expansion characteristics make it useful for ceramic and glass formulas including camera lenses.
In medical applications it is used for cancer and inflamed joints treatments and as high precision surgical tools.