Crystal Structure: hexagonal Density, g/cm3: 3.98 Refractive index: 1,775 (1.0 mm) Transmission band: 0.15 - 6 mm Thermal Expansion Coefficient:                                     8.4x10-6 Melting point (C): 2040o Hardness: Mohs scale 9

Other applications

• Sapphire is used as a substrate in gallium nitride-based light emitting diodes.
• Synthetic sapphire is exceptionally smooth on the surface as well as being extremely hard, has great compressive strength and a high resistance to mechanical corrosion. Practically free from wear, sapphire will not adhere to metal through friction even at high temperatures. These mechanical properties make sapphire extremely suitable for all of the following uses: bearings, mechanical parts, nozzles, thread guides, knife edges for balances and many more.
• Resistant to acids, corrosive liquids and radial jets of water. Transmission of heat without loss of contact with substances in fusion. Excellent for sprays and nozzles of all types, valves used in chemical applications, all parts subjected to high temperatures or in contact with acids.
• Synthetic sapphire is a very good insulator, possessing excellent dielectric properties and being non porous it is well suited for electrical apparatus. A low specific gravity with slight expansion, extremely low coefficient of friction makes sapphire ideal for all bearing applications, ball bearings, needles and roller bearings.