Quartz crystals are chiral, and exist in two forms, the normal quartz and the high-temperature quartz. The transformation from quartz to beta-quartz takes place abruptly at 573°C (846 K). Since the transformation is accompanied by a significant change in volume, it can easily induce fracturing of ceramics or rocks passing through this temperature limit.
Clear fused quartz glass is a unique material with an unrivalled combination of purity, high temperature resistance, thermal shock resistance, high electrical insulation, optical transparency and chemical inertness.
|Density||2.20 x 103 Kg/m3|
|Young's Modulus||74 x 106 KN/m2|
|Rigidity Modulus||32 x 106 KN/m2|
|Compresive Strength||20 x 106 KN/m2|
|Tensile Strength||70 x 103 KN/m2|
|Shear Strength||70 x 103 KN/m2|
|Electrical Resistivity||2 x 1019 ohm cm at 20oC
2 x 106 ohm cm at 800oC
|Dielectric Strength||10 KV/mm at 20oC
2.5 KV/mm at 500oC
|Coefficient of Expansion||0.52 x 10-6 per oC|
|Continuous Operating Temp.||>1000oC|
|Useful Optical Range||Synthetic 180 - 2000nm
Natural 275 - 2000nm
|Refractive Index||n D (589 nm) - 1.458|
|Total Metallic Impurities||10ppm (Typical)|
Fused quartz does not react with expection of hydrofluoric and at high temperatures phosphoric. There is a slow reaction with caustic alkalies at normal temperatures. There is no reaction with water and steam at moderate temperatures and pressures.
More detailed information such as transmission curves and chemical impurity levels are available on request