Fused Silica vs Fused Quartz – Exact Differences in Raw Material, Purity & Application
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- FELIX GLASS
- Issue Time
- Mar 3,2026
Summary
Compare quartz glass and borosilicate glass on composition, temperature resistance, UV transmittance, chemical stability and cost. Follow professional selection guidance for laboratory, industrial and optical applications.

# Quartz Glass vs Borosilicate Glass – Full Comparison on Properties, Cost & Applications
## 1. Introduction
Quartz glass and borosilicate glass are two mainstream heat-resistant glass materials widely adopted in laboratories, industrial production and optical equipment. Many engineers and purchasers mix up their features and make improper choices. This article conducts a comprehensive comparison covering material composition, core performance, service life, production cost and application fields, to help you select the most suitable material according to actual working conditions.
## 2. What Are Quartz Glass & Borosilicate Glass
**Quartz Glass**: Dominated by high-purity SiO₂ without extra additives. It is manufactured by melting natural quartz crystal or synthetic silica under ultra-high temperature, and classified into industrial grade, optical grade and semiconductor grade for different usage demands.
**Borosilicate Glass (Pyrex)**: Formulated with silica, boron oxide and sodium oxide. Boron is added to improve heat resistance. As a cost-effective heat-resistant glass, it is widely used in civil fields and general industrial scenarios.
3. Key Properties
| Comparison Item | Quartz Glass | Borosilicate Glass |
|---|---|---|
| Main Composition | 99.5%~99.999% SiO₂ | SiO₂ + B₂O₃ + Na₂O |
| Max Continuous Temperature | 1100°C | 450°C |
| Thermal Shock Resistance | Excellent, tolerate sharp temperature change | General, only for mild temperature fluctuation |
| Deep UV Transmittance | Full transmission down to 160nm | Almost completely block deep UV |
| Acid Resistance | Excellent | Good |
| Alkali Resistance | Poor to dilute alkali | Medium |
| Purity Level | Ultra-high purity, semiconductor available | Medium purity |