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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)