Typical Physical Properties : Melting Point: Greater than 4000F Coefficient of Thermal Expansion: 4.2 x 10-6cm/cm/C Hardness: 7.5 Moh's Scale Thermal Conductivity: 14.5 BTU/sq. ft./hr./F/in. Index of Refraction: 2.0 Thermal Stability: no change to 3090F (1700C) Average Particle Size : 1500 Spectralux : 6.0 - 8.0 Microns 3500 Spectralux : 1.90 - 2.10 Microns 4500 Spectralux : 1.65 - 1.75 Microns 5500 Spectralux : 1.40 - 1.5- Microns 6000 Spectralux : 1.20 - 1.30 Microns 7000 Spectralux : 0.95 - 1.05 Microns
