• Chemical resistance.
Sapphire is highly inert and resistant to attack in most process environments including hydrofluoric acid and the fluorine plasma applications commonly found in semiconductor wafer processing .
• Mechanical properties.
Sapphire is characterized by high toughness and solidity, and demonstrates excellent resistance in different environments ranging from cryogenic to over 1500°C. Due to this characteristics combined with chemical stability sapphire is widely used in medicine: endoscope and probe lenses, needles for thermal treatment of tumors, scalpels etc.
• Electrical properties.
Sapphire provides a high, stable dielectric constant with the electrical insulation required for LED, RF and microwave applications. • Wear properties.
With high hardness and transparency, sapphire is used for scratch proof windows in high wear applications and for precision mechanical components.
• Optical transmission.
Sapphire is characterized by high transmission in the range of UV to near IR. Given the chemical stability, high temperature and high pressure resistance sapphire is the preferred choice for window / viewport applications in high performance vacuum systems, furnaces, deep sea cameras, fire alarm systems etc.
• Surface properties.
Sapphire can be polished to very high flatness and smoothness for substrate applications and precision mechanical components.
• Thermal properties.
With a melting point over 2000°C, and high thermal conductivity sapphire is often used in many harsh process environments. | 
