Menu (ESC)

Calcium Fluoride (CaF2) Optical Material

Calcium fluoride is a non-glass, inorganic optical material. It has a fairly high heat capacity and a moderately high melting temperature among non-glass optical ceramics. The graph bars on the material properties cards below compare calcium fluoride 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

80 GPa 12 x 106 psi

Knoop Hardness


Poisson's Ratio


Shear Modulus

34 GPa 4.9 x 106 psi

Thermal Properties

Melting Onset (Solidus)

1420 °C 2590 °F

Specific Heat Capacity

860 J/kg-K 0.21 BTU/lb-°F

Thermal Conductivity

9.7 W/m-K 5.6 BTU/h-ft-°F

Thermal Expansion

19 µm/m-K

Otherwise Unclassified Properties


3.2 g/cm3 200 lb/ft3

Light Transmission Range

0.15 to 9.0 µm

Refractive Index


Common Calculations

Stiffness to Weight: Axial

14 points

Stiffness to Weight: Bending

45 points

Thermal Diffusivity

3.5 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

Ceramics and Composites: Processing Methods, Narottam P. Bansal and Aldo R. Boccaccini (editors), 2012