ForMatter/Materials/glass/Fused Quartz (High-Purity Silica Glass)
mat_glass_fused_quartz

Fused Quartz (High-Purity Silica Glass)

vitreous SiO2 glass, near-100 percent silica, low-expansion specialty glass · fused silica, fused quartz, quartz glass, synthetic fused silica, GE 124 (a common grade)
highlast updated 2026-04-28

The high-temperature, low-expansion, optically-clear glass of every UV lamp envelope, every semiconductor diffusion tube, every spectrophotometer cuvette, every halogen lamp envelope, every lab crucible that needs to survive a propane torch without cracking. Fused quartz is glass made from essentially pure silica (SiO2) — no soda, no lime, no boron — melted at very high temperature (~2000 °C) and cooled into a glass that combines exceptional optical transparency (transmits UV through near-IR), exceptional thermal stability (working temperature ~1100 °C continuous, 1500 °C peak), exceptional chemical inertness (acid- and base-resistant except hydrofluoric and hot phosphoric), and an exceptionally low coefficient of thermal expansion (~0.5 × 10⁻⁶/K — about 1/20th of soda-lime glass, allowing thermal-shock-immune use that ordinary glass cannot survive). Buy from Heraeus / GE Quartz / Momentive (industrial quantities), Edmund Optics / Thorlabs (lab and optical components).

Vitreous (non-crystalline) silicon dioxide glass, typically 99.9-99.99+ percent SiO2 by weight. Two production routes: (1) electric-furnace fused (melting natural quartz crystal in an electric arc furnace at ~2000 °C — GE 124 grade is a representative product), (2) flame fusion / synthetic CVD (chemical vapor deposition from silicon tetrachloride + water vapor — Suprasil, Heraeus's premium grade — yielding the lowest impurity levels and best UV transmittance). Density 2200 kg/m³. Refractive index 1.46 at the sodium-D line. Coefficient of thermal expansion 0.55 × 10⁻⁶ /K (the property that enables thermal-shock survival). Working temperature 1100 °C continuous, 1500 °C peak. Softening point 1683 °C. Modulus of elasticity 73 GPa. Tensile strength 50 MPa untempered, higher when fire-polished. Chemical inertness: resists all common acids and bases except HF and hot H3PO4; the optical-vacuum-laboratory standard for chemical containment. Optical transmission: synthetic-grade fused silica (Suprasil) transmits >90 percent from 200 nm UV through 2200 nm near-IR; the low-OH grades (KrF / ArF excimer-laser optics) extend deeper into UV. Polishes to optical-flat surfaces (lambda/20 typical for premium optics). Cuts and grinds with diamond tooling; cannot be drawn or blown easily because of the high working temperature.

Mechanical

  • density · kg/m³2200
  • refractive index nd1.46
  • coefficient thermal expansion · /K5.5e-07
  • working temperature · °C1100
  • softening point · °C1683
source: Heraeus Suprasil technical data; GE Quartz product data; ASTM E438 standard for laboratory glassware

Sustainability

  • embodied carbon · kg CO₂e/kg8.5
  • recyclabilitymoderate — clean fused-quartz scrap recycles back into the melt; coated optical components are difficult to reclaim
  • biodegradableFalse
  • certificationsASTM E438 (laboratory glassware), specialty-optic grades carry per-application certifications (KrF/ArF for excimer-laser optics, Class 0 for semiconductor process)
  • localityprimary production by Heraeus (Germany), Momentive (US), Tosoh (Japan), General Electric (historic US source); designer-quantity for lab / optical use via Edmund Optics, Thorlabs, McMaster
source: Editorial estimate — fused-quartz manufacture is energy-intensive (the 2000 °C melt), driving the per-kg carbon load well above ordinary float glass.
visual
essentially water-clear; the lowest-iron grades are optically indistinguishable from clean air at hand-thickness; specialty UV-grades transmit deeper into UV than the human eye can see
tactile
smooth and slightly cooler than soda-lime glass at touch; ground edges crisp; the lab-glassware feel of premium quartz tubing under the hand
weight perception
lighter than soda-lime per volume (lower density)
acoustic
a high clear ring when struck — the high modulus and low damping give fused quartz a piano-string acoustic
Simon Winchester (living — quote)

LIGO's instruments showed without doubt that a series of gravitational waves, arriving after billions of years of travel from the universe's outer edges, had passed by and through Earth and, for the fleeting moment of their passage, changed our planet's shape.

Winchester, The Perfectionists: How Precision Engineers Created the Modern World (HarperCollins, 2018), Chapter 10, 'On the Necessity for Equipoise'. The LIGO test masses are 40-kg fused-silica cylinders polished to surface figure better than λ/100 — the most precisely shaped objects in human history, and the application that has driven fused-silica polishing technology to its current limits.

PBR starter values

finish · transparent — open for table, JSON, host snippets, downloads

Principled BSDF defaults derived from the sphere transparent finish. Reasonable seed for Blender, Substance, Keyshot, Rhino — tune per material. Or grab the whole library at once: ForMaterials library →

# finish:                   transparent
albedo                      #e8f0f4
metallic                    0.00
roughness                   0.05
ior                         1.50
transmission                1.00
clearcoat                   0.00
sheen                       0.00
anisotropic                 0.00
thickness                   1.00
attenuation_distance        0.60
copy as JSON 
{
  "albedo": "#e8f0f4",
  "metallic": 0.0,
  "roughness": 0.05,
  "ior": 1.5,
  "transmission": 1.0,
  "clearcoat": 0.0,
  "sheen": 0.0,
  "anisotropic": 0.0,
  "thickness": 1.0,
  "attenuation_distance": 0.6
}
Blender 4.x Python 
# Blender 4.x — Principled BSDF
# Fused Quartz (High-Purity Silica Glass) · finish: transparent
import bpy
mat = bpy.data.materials.new(name="mat_glass_fused_quartz")
mat.use_nodes = True
bsdf = mat.node_tree.nodes["Principled BSDF"]
bsdf.inputs["Base Color"].default_value         = (0.807, 0.8714, 0.9047, 1.0)
bsdf.inputs["Metallic"].default_value           = 0.000
bsdf.inputs["Roughness"].default_value          = 0.050
bsdf.inputs["IOR"].default_value                = 1.500
bsdf.inputs["Transmission Weight"].default_value = 1.000
bsdf.inputs["Coat Weight"].default_value        = 0.000
bsdf.inputs["Sheen Weight"].default_value       = 0.000
bsdf.inputs["Anisotropic"].default_value        = 0.000
KeyShot Python (lux) 
# KeyShot 11+ — lux Python API, Generic material
# Fused Quartz (High-Purity Silica Glass) · finish: transparent
# Run from Window → Scripting Console
import lux
mat = lux.createMaterial(name="mat_glass_fused_quartz", materialType="Generic")
mat.setProperty("diffuse",      (232, 240, 244))   # 8-bit sRGB
mat.setProperty("metallic",     0.000)
mat.setProperty("roughness",    0.050)
mat.setProperty("indexOfRefraction", 1.500)
mat.setProperty("transparency", 1.000)
mat.setProperty("coatingWeight", 0.000)
Substance pbrMetalRough 
{
  "_format": "Substance Designer / Painter \u2014 pbrMetalRough constants",
  "_about": "Fused Quartz (High-Purity Silica Glass) \u00b7 finish: transparent",
  "baseColor": {
    "r": 0.807,
    "g": 0.8714,
    "b": 0.9047
  },
  "metallic": 0.0,
  "roughness": 0.05,
  "ior": 1.5,
  "opacity": 0.0,
  "anisotropyLevel": 0.0,
  "_notes": "Channels listed are the standard Substance pbrMetalRough output. Drop into a Uniform Color node per channel, or as the constant input on a layered stack."
}
glTF 2.0 Metallic-Roughness 
{
  "asset": {
    "version": "2.0",
    "generator": "ForMatter"
  },
  "materials": [
    {
      "name": "mat_glass_fused_quartz",
      "pbrMetallicRoughness": {
        "baseColorFactor": [
          0.807,
          0.8714,
          0.9047,
          1.0
        ],
        "metallicFactor": 0.0,
        "roughnessFactor": 0.05
      },
      "extensions": {
        "KHR_materials_transmission": {
          "transmissionFactor": 1.0
        }
      }
    }
  ]
}
USD Preview Surface 
# USD Preview Surface — UsdShade.MaterialLook prim attributes
# Fused Quartz (High-Purity Silica Glass) · finish: transparent
def Material "mat_glass_fused_quartz" {
    token outputs:surface.connect = </mat_glass_fused_quartz/PreviewSurface.outputs:surface>

    def Shader "PreviewSurface" {
        uniform token info:id = "UsdPreviewSurface"
        color3f inputs:diffuseColor = (0.807, 0.8714, 0.9047)
        float   inputs:metallic     = 0.000
        float   inputs:roughness    = 0.050
        float   inputs:ior          = 1.500
        float   inputs:opacity      = 0.000
        float   inputs:clearcoat    = 0.000
        token   outputs:surface
    }
}
↓ download glTF material
Substitutes
Optical Crown Glass (BK7)
Borosilicate Glass
Where to buyhttps://www.mcmaster.com/glass/

Second life

repairabilityvery low — fused quartz is brittle, hard to weld, hard to repair; replacement standard.
recyclabilitylow — high-purity fused quartz cullet is segregated; specialty.
disposal pathspecialty quartz recycler.
typical longevity500 years (typical)
failure modes
  • thermal-shock fracture (better than soda-lime but worse than borosilicate at large gradients)
  • devitrification at sustained 1000+ °C
  • surface scratching

Heraeus / Momentive fused-quartz technical literature; LIGO Caltech mirror-substrate literature.

Citations

  • en.wikipedia.org — Fused quartz
  • standard · ASTM E438 — Standard Specification for Glasses in Laboratory Apparatus
  • book · Winchester, The Perfectionists: How Precision Engineers Created the Modern World (HarperCollins, 2018), Chapter 10 — LIGO test masses (40-kg fused-silica cylinders) as the contemporary frontier of fused-silica precision polish.

Further reading