FUSED SILICA MATERIAL DATA
Technical Specifications: Quartz Glass Properties
Comprehensive material properties and performance data for high-purity quartz glass, engineered for the most demanding semiconductor, optical and high-temperature applications. The figures below are typical material values for fused silica; the exact grade is matched to each application.
Material Properties Overview
Our high-purity quartz glass exhibits exceptional properties across all critical parameters. Manufactured from premium quartz using advanced fusion techniques, it delivers consistent, reliable performance in semiconductor fabrication, optical systems and high-temperature use, verified through rigorous in-house testing.
Physical & Mechanical Properties
Quartz glass combines low density with high hardness and dimensional stability, ideal for precision components needing minimal weight and maximum durability.
| Mohs Hardness | 5.5 – 6.5 |
| Compressive Strength | 1100 MPa |
| Flexural Strength (20°C) | 67 MPa |
| Tensile Strength | 48 MPa |
| Young’s Modulus (20°C) | 72 GPa |
| Shear Modulus | 31 GPa |
| Bulk Modulus | 37 GPa |
| Poisson’s Ratio | 0.17 |
| Density (20°C) | 2.2 g/cm³ |
Thermal Properties
Exceptional thermal-shock resistance and very low thermal expansion suit rapid temperature cycling — quartz can move between high temperature and room temperature without cracking.
| Annealing Point | ≈ 1215 °C |
| Strain Point | ≈ 1120 °C |
| Max. Working Temp (Continuous) | 1200 °C |
| Max. Working Temp (Short Term) | 1300 °C |
| Thermal Expansion (20–300°C) | 5.5 × 10⁻⁷ /°C |
| Thermal Conductivity (20°C) | 1.4 W/(m·K) |
| Specific Heat (20°C) | 670 J/(kg·K) |
| Thermal Diffusivity (20°C) | 9.5 × 10⁻⁷ m²/s |
| Softening Point | ≈ 1680 °C |
Electrical Properties
Excellent electrical insulation with high resistivity and low dielectric loss — ideal for high-frequency use and electrical isolation in semiconductor processing equipment.
| Resistivity (20°C) | > 10¹⁸ Ω·cm |
| Resistivity (350°C) | 7 × 10⁷ Ω·cm |
| Dielectric Constant (1 MHz, 20°C) | 3.75 |
| Dielectric Strength | 25 – 40 kV/mm |
| Dielectric Loss Factor (1 MHz) | < 1 × 10⁻⁴ |
| Dielectric Loss Factor (1 GHz) | < 6 × 10⁻⁴ |
Optical Properties
Excellent UV transmission and optical clarity make quartz glass essential for spectroscopy, laser systems and optical-fiber applications, with minimal absorption and scattering.
| Refractive Index (589 nm, 20°C) | 1.4585 |
| Refractive Index (1060 nm) | 1.4496 |
| Transmission Range | 185 – 2500 nm |
| UV Transmission (254 nm, 10 mm) | > 90% |
| Abbe Number | 67.8 |
| Stress Optical Coefficient | 3.5 × 10⁻⁶ MPa⁻¹ |
Chemical Composition & Purity
High-purity fused silica with very low metallic impurities ensures contamination-free processing. The exact purity and OH grade are matched to your application and verified by analytical methods on every production batch.
| SiO₂ Content | High purity |
| OH Content | Grade-matched (UV / IR) |
| Metallic Impurities | Very low |
| Alkali Content (Na, K) | Very low |
| Batch Verification | Analytical (e.g. ICP-MS) |
| Acid Resistance | Excellent (except HF) |
Additional Properties
Further characteristics — acoustic, radiation and surface properties — relevant to specialised research and industrial processes.
| Acoustic Velocity (Longitudinal) | 5968 m/s |
| Acoustic Velocity (Transverse) | 3764 m/s |
| Radiation Resistance | Good |
| Permeability (He at 700°C) | Low |
| Surface Energy | ≈ 300 mJ/m² |
| Outgassing Rate (Vacuum) | Very low |
Performance Comparison
Understanding how quartz glass compares with other materials helps you select the optimal solution. Below is a comparison with common alternatives.
| Property | Quartz Glass | Borosilicate Glass | Sapphire | Alumina Ceramic |
|---|---|---|---|---|
| Max Temperature (°C) | 1200 | 500 | 1800 | 1600 |
| Thermal Expansion (×10⁻⁶/K) | 0.55 | 3.3 | 5.3 | 7.2 |
| Thermal Shock Resistance | Excellent | Good | Fair | Fair |
| UV Transmission | Excellent | Poor | Good | None |
| Chemical Purity | High | Lower | High | Standard |
| Relative Cost | Medium | Low | Very High | Medium |
Need Detailed Technical Data?
Contact our engineering team for grade-specific material data and application guidance, or see how these properties are achieved on our manufacturing process page and across our product range.