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Crystalline (Alpha) Quartz Optical Material

Alpha quartz is a non-glass, inorganic optical material. It has a fairly high melting temperature among non-glass optical ceramics. In addition, it has a moderately low density and a moderately high heat capacity. The graph bars on the material properties cards below compare alpha quartz to other non-glass optical ceramics (top) and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.

Mechanical Properties

Elastic (Young's, Tensile) Modulus

91 GPa 13 x 106 psi

Knoop Hardness


Poisson's Ratio


Shear Modulus

31 GPa 4.5 x 106 psi

Thermal Properties

Melting Onset (Solidus)

1590 °C 2890 °F

Specific Heat Capacity

720 J/kg-K 0.17 BTU/lb-°F

Thermal Conductivity

8.5 W/m-K 4.9 BTU/h-ft-°F

Thermal Expansion

9.5 µm/m-K

Otherwise Unclassified Properties


2.7 g/cm3 170 lb/ft3

Light Transmission Range

0.13 to 3.4 µm

Refractive Index


Common Calculations

Stiffness to Weight: Axial

19 points

Stiffness to Weight: Bending

57 points

Thermal Diffusivity

4.4 mm2/s

Followup Questions

Further Reading

Handbook of Optical Materials, Marvin J. Weber, 2003

Handbook of Optical Constants of Solids, Edward D. Palik (editor), 1998