Yttrium is a chemical element with symbol Y and atomic number 39. It is a silvery-metallic transition metal chemically similar to the lanthanides and it has often been classified as a "rare earth element". Yttrium is almost always found combined with the lanthanides in rare earth minerals and is never found in nature as a free element. Its only stable isotope, Y, is also its only naturally occurring isotope.
Yttrium has a silvery-metallic lustre. Yttrium turnings ignite in air. Yttrium is found in most rare-earth minerals. Moon rocks contain yttrium and yttrium is used as a "phosphor" to produce the red colour in television screens.