Grey as a metal; white as yttrium oxide
In air it is relatively stable whereas in water it strongly reacts producing hydrogen and yttrium hydroxide.
Half of the yttrium consumed worldwide has been used in the manufacture of luminescent material until the market breakthrough of LEDs. Meanwhile, this has shifted significantly. Yttrium is applied in high-performance ceramics, such as for the coating of aircraft engines. It is also used in the dental industry as well as in the manufacture of laser crystals. Moreover, yttrium is used in mixed oxides for exhaust gas catalysts.