Quartz
Quartz
Single crystalline Quartz (SiO2) is a crystal that occurs both naturally and is produced synthetically by means of hydrothermal synthesis. In the wavelength range between 0.3 µm and 2.7 µm, the transmission ratio is over 90 %. In contrast to quartz glass, monocrystalline quartz has strong birefringence. Quartz exists as alpha quartz (low quartz) by default, at a temperature above 573 °C the crystal structure changes to beta quartz (high quartz). This is a reversible process, but can lead to cracks and fractures in the material.
Quartz is mainly used as a polarizer, in piezoelectric devices, in FIR optics, as a VUV filter, and in microscopes.
Optical and spectral properties | |
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Transmission range in µm (minimum 10%) | 0,15‐4,8
|
Transmission range in µm (minimum 50%) | 0,15‐4,1 |
Refractive index @633nm | 1,543 (no) 1,552 (neo) |
Reflection losses in % at 1 surface | 6.94 @2.9µm
|
Reflection losses, % for two surfaces | 8,8@0,6µm
|
dN/dT in 1/K | 5 · 10-6
|
Physical properties | |
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Density in g/cm3 | 2,65
|
Melting point in °C | 1710
|
Specific heat capacity in J/(kg · K) | 710
|
Thermal conductivity in W/(m · K) | 10,7 (parallel) 6.2 (perpendicular) |
Thermal expansion in 1/K | 13,2 · 10-6 (parallel) 7,9 · 10-6 (perpendicular) |
Dielectric constant | 4,34 (parallel) 4.27 (perpendicular) |
Solubility in water in g/100g | insoluble |
Mohs hardness | 7 |
Knoop hardness in kg/mm² | 710
|
Material type | single crystalline, synthetic
|
Crystal type | trigonal |
Crystal structure | amorphous
|
Lattice constant in Å | a = 4,914 c = 12,405 |
Elastic coefficient in GPa | C11 = 87 C12 = 7 C33 = 106 C44 = 58 C13 = 13 C14 = -18 |
Young's Modulus (E) in Gpa | 97,2 (parallel) 76.5 (perpendicular) |
Shear Modulus (G) in GPa | 31,14 |
Bulk Modulus (K) in GPa | 98 |
Apparent elastic limit in MPa | 55
|
Poisson's ratio | 0,17
|
Spectral properties | |
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sample thickness: 2 mm |