SiO2 (Quartz Crystal)
Optically, Crystalline Quartz is used extensively as a wave retardation medium. The birefringent properties of Quartz are of use in quarter-wave plates and in polarisers. Quartz should not be processed or used at temperatures greater than 490 °C. Crystalline quartz is also used for electronic filters and resonators. However, Crystran Ltd. does not deal in material for this application.
Physical and optical properties
| Transmission Range : | 0.18 to 3.5 μm (also >40 μm) |
| Refractive Index : | No 1.54421; Ne 1.55333 at 0.6 μm |
| Reflection Loss : | 8.8% at 0.6 μm (2 surfaces) |
| Absorption Coefficient : | n/a |
| Reststrahlen Peak : | n/a |
| dn/dT : | +5 x 10-6/°C |
| dn/dμ = 0 : | 1.3 μm |
| Density : | 2.649 g/cc |
| Melting Point : | 1710 °C |
| Thermal Conductivity : | 10.7 (para) 6.2 (perp) W m-1 K-1 at 323 K |
| Thermal Expansion : | 7.1 (para) 13.2 (perp) x 10-6/°C |
| Hardness : | Knoop 741 with 500g indenter |
| Specific Heat Capacity : | 710 J Kg-1 K-1 |
| Dielectric Constant : | 4.34 (para) 4.27 (perp) at 30MHz |
| Youngs Modulus (E) : | 97.2 (para) 76.5 (perp) GPa |
| Shear Modulus (G) : | 31.14 GPa |
| Bulk Modulus (K) : | 36.4 GPa |
| Elastic Coefficients : | C11=87 C12=7 C44=58 C13=13 C14=(-)18 C33=106 |
| Apparent Elastic Limit : | 41MPa (5950psi) |
| Poisson Ratio : | n/a |
| Solubility : | Insoluble in water |
| Molecular Weight : | 60.06 |
| Class/Structure : | Trigonal (hex) P3(2)21 (RH) and P3(1)21 (LH) |
No = Ordinary Ray Ne = Extraordinary Ray
µm |
No |
Ne |
µm |
No |
Ne |
µm |
No |
Ne |
0.193 |
1.661 |
1.675 |
0.213 |
1.632 |
1.645 |
0.222 |
1.622 |
1.634 |
0.226 |
1.619 |
1.630 |
0.248 |
1.602 |
1.613 |
0.257 |
1.596 |
1.607 |
0.280 |
1.585 |
1.596 |
0.308 |
1.576 |
1.586 |
0.325 |
1.571 |
1.581 |
0.351 |
1.565 |
1.575 |
0.400 |
1.558 |
1.567 |
0.458 |
1.552 |
1.561 |
0.488 |
1.550 |
1.559 |
0.515 |
1.548 |
1.557 |
0.532 |
1.547 |
1.556 |
0.590 |
1.544 |
1.553 |
0.633 |
1.543 |
1.552 |
0.670 |
1.541 |
1.551 |
0.694 |
1.541 |
1.550 |
0.755 |
1.539 |
1.548 |
0.780 |
1.539 |
1.548 |
0.800 |
1.538 |
1.547 |
0.820 |
1.538 |
1.547 |
0.860 |
1.537 |
1.547 |
0.980 |
1.535 |
1.546 |
1.064 |
1.534 |
1.543 |
1.320 |
1.531 |
1.539 |
1.550 |
1.528 |
1.536 |
2.010 |
1.521 |
1.529 |
BQuartz is mined naturally, but more commonly produced synthetically in large, long-faceted crystals. Quartz is positive birefringent. Be careful not to confuse terminology in this material, as "Fused Quartz" is often used to denote the glassy non-crystalline form better known as Silica.
Normal Quartz is Alpha Quartz and normally RH rotating. LH rotating is available on special order.
At temperatures >490°C, Crystal Quartz starts to revert to glassy state, a process which is complete by 530°C. At this time, as annealling is unlikely, fracture of component is probable.
WEBLINKS:
Webmineral.com - Has further information on Quartz Crystal.
Rockhoundingar.com - Has information regarding the handedness of Quartz crystals.
Washington University - Has articles on research into this material.
Quartz-Dyne Inc. - Has information regarding Alpha Quartz.
Tags: SiO2 (Quartz Crystal)