SAPPHIRE

Sapphire properties 

Chemical formula - Al₂O₃
Melting point - 2053⁰ C
Moh Hardness - 9 (for compare: diamond = 10)
Transmission - 0.2 micron (0%), 0.4 micron (88%), 4.2 micron (88%), 5 micron (78%), 6.3 micron (0%)
Deflection coeff. - 1.777
Density - 3.98 g/cm
Tensile Strength - 300 to 400 MPa
Volume Resistivity - 10¹⁴ Om/cm
Crystal Structure - Hex-Rhomb

As it shown, sapphire is very hard and calcitrant. In most cases it is impossible to add a shape to sapphire in any other way except Shaped Crystal Growth.

Application

- IR optics
- Scratch resistance windows
- High temperature insulators
- Precise mechanics
- Human bones prosthesis
- Substrates for epitaxy
- High pressure lamps

Other applications (in Russian)