Quartz

Material
Quartz 

Single crystalline Quartz is mined naturally, but more commonly produced synthetically in large, long faceted crystals. It is grown by hydrothermal method in autoclaves. It has trigonal crystal structure with right-hand or left-hand modification. Quartz is anisotropic monoaxial crystal. It has low stress birefringence and highest refractive index homogeneity. The optical transmission range of crystal quartz is 0.15-4 microns. Quartz corresponds to the best natural material by its physical properties. It contains neither electrical nor optical twins and there are no cracks and chippings. Crystals of synthetic quartz show high transmittance over a large spectral range from IR to UV.

Optically, crystalline quartz is used extensively as a wave retardation medium, using the birefringent properties for use in quarter-wave plates and in polarizes, for UV-lenses and windows.

Properties

Optical Property

Transmission Range, µm

0.4 – 3.5

Refractive Index, at 1 µm

no = 1.5350
na = 1.5438

Reflection Loss, % for two surfaces at 2 µm

8.2

dN/dT, 1/°C

5 x 10-6

Physical Property

Density, g/cm3 (20°C)

2.635 – 2.660

Solubility, in water

insoluble

Type of Material

trigonal, point group 32,
a = 4.9138 Å,
c = 5.4052 Å

Melting Temperature, °C

1467

Thermal Conductivity, W/(m · K) at – 253 °C  parallel C-axis:

720.0

Thermal Conductivity, W/(m · K) at – 253 °C  perpendicular C-axis:

370.0

Thermal Conductivity, W/(m · K) at – 79 °C parallel C-axis:

20.0

Thermal Conductivity, W/(m · K) at – 79 °C perpendicular C-axis:

10.0

Thermal Conductivity, W/(m · K) at 50 °C parallel C-axis:

10.7

Thermal Conductivity, W/(m · K) at 50 °C perpendicular C-axis:

6.2

Thermal Expansion, 1/°C at 0 to – 20 °C parallel C-axis:

7.64 x 10-6

Thermal Expansion, 1/°C at 0 to – 20 °C perpendicular C-axis:

14.00 x 10-6

Mohs Hardness, indenter load 500g

740

Specific Heat Capacity, J/(kg · K) at 10 °C

744

Dielectric Constant, for 3 x 107 Hz at 52 °C parallel C-axis:

4.34

Dielectric Constant, for 3 x 107 Hz at 52 °C perpendicular C-axis:

4.27

Young’s Modulus, GPa parallel C-axis:

76.5

Young’s Modulus, GPa perpendicular C-axis:

97.2

Shear Modulus (G), GPa

31.14

Bulk Modulus (K), GPa

36.4

Elastic Coefficient, GPa

C11 = 86.6
C12 = 6.7
C13 = 12.4
C14 = 17.8
C33 = 106.4
C44 = 58.0

Debye Temperature, °C

197

Rupture Modulus, MPa

41

Knoop Hardness, kg/mm2

741