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Fused Silica vs ZnSe

Glass · grade comparison

Fused Silica and ZnSe are both glass grades. Fused Silica is harder — 700 HV against 105 HV for ZnSe — which matters for wear surfaces and threads. Fused Silica is lighter (2.2 g/cm³ vs 5.27 g/cm³ for ZnSe) and Fused Silica is stiffer (72 GPa vs 67.2 GPa). On the shop floor, ZnSe machines more easily (fair vs not recommended) and Fused Silica sits in a lower cost tier (standard, $$) than ZnSe (high, $$$$).

Fused SilicaChoose it when surface hardness matters, or when weight is the constraint.

ZnSeChoose it when the part is machined in volume.

Fused Silica vs ZnSe: properties

Fused SilicaZnSe

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

72 GPa10.4 Msi
67.2 GPa9.7 Msi

Shear Modulus

31 GPa4.5 Msi
26.6 GPa3.9 Msi

Bulk Modulus

37 GPa5.4 Msi
40 GPa5.8 Msi

Poisson's Ratio

0.17
0.28

Elongation at Break

0%
—

Compressive Strength

1,150 MPa167 ksi
—

Flexural Strength

67 MPa9.7 ksi
55 MPa8 ksi

Shear Strength

30 MPa4.4 ksi
—

Fracture Toughness (K_IC)

0.75 MPa·√m0.68 ksi·√in
0.5 MPa·√m0.46 ksi·√in

Hardness, Vickers

700 HV
105 HV

Hardness, Knoop

560 HK
110 HK

Hardness, Mohs

6
2.5

Same in both: Tensile Strength (Ultimate) 50 MPa7.3 ksi

Physical

Density and transition temperatures.

Density

2.2 g/cm³0.08 lb/in³
5.27 g/cm³0.19 lb/in³

Melting Point (Solidus)

1,713°C3,115 °F
1,525°C2,777 °F

Refractive Index

1.459
2.403

Light Transmission

92%
71%

Same in both: Porosity 0%

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

1.4 W/m·K0.8 BTU/hr·ft·°F
18 W/m·K10.4 BTU/hr·ft·°F

Specific Heat Capacity

740 J/kg·K0.18 BTU/lb·°F
339 J/kg·K0.08 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

0.55 µm/m·K0.31 µin/in·°F
7.1 µm/m·K3.9 µin/in·°F

Max Service Temperature (continuous)

1,100°C2,012 °F
300°C572 °F

Same in both: Min Service Temperature -200°C-328 °F

Electrical

Conductivity and insulation.

Electrical Resistivity

1×10¹⁶ Ω·m3.94×10²³ µΩ·in
1×10¹⁰ Ω·m3.94×10¹⁷ µΩ·in

Dielectric Strength

30 kV/mm762 V/mil
—

Dielectric Constant (1 MHz)

3.8
9.1

Dissipation Factor (1 MHz)

1×10⁻⁴
—

Volume Resistivity

1×10¹⁸ Ω·cm
1×10¹² Ω·cm

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

95 / 100
55 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

10 / 100
45 / 100

Polishability

98 / 100
85 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

55 MJ/kg23,646 BTU/lb
—

Embodied Carbon (primary production)

4 kg CO₂/kg
—

Embodied Water

80 L/kg9.6 gal/lb
—

Typical Recycled Content

0%
—

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

23 kN·m/kg
9 kN·m/kg

Specific Stiffness (E / density)

32.7 MN·m/kg
12.8 MN·m/kg

Thermal Diffusivity

0.8 mm²/s
10.1 mm²/s

Same in both: Thermal Shock Resistance Index 2

Strength versus weight

Yield strength against density for every glass grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.

501002005002.533.5Density (g/cm³)Yield strength (MPa) — log scaleFused Silica

Manufacturing and finishing

CapabilityFused SilicaZnSe
Default conditionAnnealed Glass—
Relative cost$$ Standard$$$$ High
Min. machined wall——
Best machined surface——

Fused Silica vs ZnSe — frequently asked

What is the difference between Fused Silica and ZnSe?

Fused Silica and ZnSe are both glass grades. Fused Silica is harder — 700 HV against 105 HV for ZnSe — which matters for wear surfaces and threads. Fused Silica is lighter (2.2 g/cm³ vs 5.27 g/cm³ for ZnSe) and Fused Silica is stiffer (72 GPa vs 67.2 GPa).

Which is cheaper, Fused Silica or ZnSe?

Fused Silica is the lower-cost material: it sits in the standard tier ($$) while ZnSe is high ($$$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.

Which is easier to machine, Fused Silica or ZnSe?

ZnSe. Its machinability rates fair (45/100) against not recommended (10/100) for Fused Silica.

Ready to make it?

Upload a CAD file and FabDigit prices the part in Fused Silica and ZnSe side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.

Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.