# Fused Silica (Fused Quartz)

Fused silica is a glass-type material. It has a fairly low density among the glass and glass-ceramics in the database.

The properties of fused silica include two common variations. This page shows summary ranges across both of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare fused silica to other glass and glass-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

Compressive (Crushing) Strength

1100 *MPa* 160 *x 10 ^{3} psi*

Elastic (Young's, Tensile) Modulus

73 *GPa* 11 *x 10 ^{6} psi*

Flexural Strength

67 *MPa* 9.7 *x 10 ^{3} psi*

Knoop Hardness

570

Poisson's Ratio

0.17

Shear Modulus

31 *GPa* 4.5 *x 10 ^{6} psi*

Tensile Strength: Ultimate (UTS)

50 *MPa* 7.2 *x 10 ^{3} psi*

## Thermal Properties

Maximum Temperature: Decomposition

1100 *°C* 2010 *°F*

Maximum Temperature: Mechanical

1080 *°C* 1980 *°F*

Melting Onset (Solidus)

1900 *°C* 3450 *°F*

Specific Heat Capacity

720 *J/kg-K* 0.17 *BTU/lb-°F*

Thermal Conductivity

1.4 *W/m-K* 0.79 *BTU/h-ft-°F*

Thermal Expansion

0.5 *µm/m-K*

## Electrical Properties

Dielectric Constant (Relative Permittivity) At 1 MHz

3.8

Dielectric Strength (Breakdown Potential)

30 *kV/mm* 1.2 *V/mil*

Electrical Dissipation At 1 MHz

0.00011

Electrical Resistivity Order of Magnitude

14 *10 ^{x} Ω-m*

## Otherwise Unclassified Properties

Density

2.2 *g/cm ^{3}* 140

*lb/ft*

^{3}Light Transmission Range

0.16 to 3.5 *µm*

Refractive Index

1.5

## Common Calculations

Stiffness to Weight: Axial

18 *points*

Stiffness to Weight: Bending

63 *points*

Strength to Weight: Axial

6.3 *points*

Strength to Weight: Bending

14 *points*

Thermal Diffusivity

0.85 *mm ^{2}/s*

Thermal Shock Resistance

97 *points*

## Followup Questions

## Further Reading

Ceramic and Glass Materials: Structure, Properties and Processing, James F. Shackelford and Robert H. Doremus (editors), 2008

Glass: Mechanics and Technology, Eric Le Bourhis, 2007

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