What are the properties of aluminum oxide?

Aluminum oxide, also known as alumina, is a compound of aluminum and oxygen with the chemical formula Al2O3. It is a white solid that is insoluble in water but soluble in acid and base. It has a high melting point (over 2000掳C), high hardness, and is chemically inert. Aluminum oxide is also a good electrical insulator and has a high refractive index. It is used in various applications, including abrasives, refractory materials, and as a catalyst in chemical processes. Additionally, it is biocompatible and is used in medical implants and dental materials.