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Alpha-Quartz vs GaAs

Glass · grade comparison

Alpha-Quartz and GaAs are both glass grades. GaAs is the stronger of the two: tensile strength 70 MPa (10.2 ksi) against 55 MPa (7.98 ksi) for Alpha-Quartz, about 27% more. Alpha-Quartz is harder — 1,150 HV against 600 HV for GaAs — which matters for wear surfaces and threads. Alpha-Quartz is lighter (2.65 g/cm³ vs 5.32 g/cm³ for GaAs) and Alpha-Quartz runs hotter in service (500°C vs 460°C continuous). On the shop floor, GaAs machines more easily (fair vs not recommended).

Alpha-QuartzChoose it when surface hardness matters, or when weight is the constraint.

GaAsChoose it when strength drives the design, or when the part is machined in volume.

Alpha-Quartz vs GaAs: properties

Alpha-QuartzGaAs

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

87 GPa12.6 Msi
85.5 GPa12.4 Msi

Shear Modulus

31 GPa4.5 Msi
32.9 GPa4.8 Msi

Bulk Modulus

38 GPa5.4 Msi
76 GPa11 Msi

Poisson's Ratio

0.17
0.31

Tensile Strength (Ultimate)

55 MPa8 ksi
70 MPa10.2 ksi

Compressive Strength

1,700 MPa247 ksi
700 MPa102 ksi

Flexural Strength

110 MPa16 ksi
90 MPa13.1 ksi

Shear Strength

90 MPa13.1 ksi
55 MPa8 ksi

Fracture Toughness (K_IC)

0.85 MPa·√m0.77 ksi·√in
0.44 MPa·√m0.4 ksi·√in

Hardness, Vickers

1,150 HV
600 HV

Hardness, Knoop

741 HK
731 HK

Hardness, Mohs

7
4.5

Same in both: Elongation at Break 0%

Physical

Density and transition temperatures.

Density

2.65 g/cm³0.1 lb/in³
5.32 g/cm³0.19 lb/in³

Melting Point (Solidus)

1,710°C3,110 °F
1,238°C2,260 °F

Refractive Index

1.544
3.28

Light Transmission

92%
54%

Same in both: Porosity 0%

Thermal

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

Thermal Conductivity

8 W/m·K4.6 BTU/hr·ft·°F
55 W/m·K31.8 BTU/hr·ft·°F

Specific Heat Capacity

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

Thermal Expansion (CTE, 20–100 °C)

11.5 µm/m·K6.4 µin/in·°F
5.7 µm/m·K3.2 µin/in·°F

Max Service Temperature (continuous)

500°C932 °F
460°C860 °F

Min Service Temperature

-270°C-454 °F
-269°C-452 °F

Electrical

Conductivity and insulation.

Electrical Resistivity

1×10¹² Ω·m3.94×10¹⁹ µΩ·in
1,000,000 Ω·m3.94×10¹³ µΩ·in

Dielectric Strength

25 kV/mm635 V/mil
40 kV/mm1,016 V/mil

Dielectric Constant (1 MHz)

4.6
12.9

Dissipation Factor (1 MHz)

2×10⁻⁴
6×10⁻⁴

Volume Resistivity

1×10¹⁴ Ω·cm
1×10⁸ Ω·cm

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

92 / 100
55 / 100

Manufacturability

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

Machinability

6 / 100
35 / 100

Polishability

95 / 100
92 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

250 MJ/kg107,481 BTU/lb
2,000 MJ/kg859,846 BTU/lb

Embodied Carbon (primary production)

18 kg CO₂/kg
130 kg CO₂/kg

Embodied Water

60 L/kg7.2 gal/lb
900 L/kg108 gal/lb

Typical Recycled Content

0%
5%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

21 kN·m/kg
13 kN·m/kg

Specific Stiffness (E / density)

32.8 MN·m/kg
16.1 MN·m/kg

Thermal Diffusivity

4.1 mm²/s
31.6 mm²/s

Thermal Shock Resistance Index

0
8

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 scale

Manufacturing and finishing

CapabilityAlpha-QuartzGaAs
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

Alpha-Quartz vs GaAs — frequently asked

Is GaAs stronger than Alpha-Quartz?

Yes. GaAs has a typical tensile strength of 70 MPa (10.2 ksi) against 55 MPa (7.98 ksi) for Alpha-Quartz — about 27% more.

Which is cheaper, Alpha-Quartz or GaAs?

Both sit in the same relative cost tier ($$$$, high); the part price will be decided by machining time, tolerance and quantity rather than by the material.

Which is easier to machine, Alpha-Quartz or GaAs?

GaAs. Its machinability rates fair (35/100) against not recommended (6/100) for Alpha-Quartz.

Ready to make it?

Upload a CAD file and FabDigit prices the part in Alpha-Quartz and GaAs 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.