Yttrium oxide is Y2O3. It is an air-stable, white solid substance. Yttrium oxide is used as a common starting material for both materials science as well as inorganic compounds.
Yttrium oxide is an excellent mineralizing agent for spinel formation. It has a high melting point(2450oC), chemical stability, low coefficient of thermal expansion, high transparency for both visible (70%) and infrared (60%) light, low cut off energy of photons.