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LiF vs Sapphire

Glass · grade comparison

LiF and Sapphire are both glass grades. Sapphire is harder — 2,000 HV against 105 HV for LiF — which matters for wear surfaces and threads. LiF is lighter (2.64 g/cm³ vs 3.98 g/cm³ for Sapphire) and Sapphire is stiffer (400 GPa vs 64.8 GPa). On the shop floor, LiF machines more easily (poor vs not recommended) and Sapphire sits in a lower cost tier (standard, $$) than LiF (high, $$$$).

LiFChoose it when weight is the constraint, or when the part is machined in volume.

SapphireChoose it when surface hardness matters, or when the part sees heat.

LiF vs Sapphire: properties

LiFSapphire

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

64.8 GPa9.4 Msi
400 GPa58 Msi

Shear Modulus

55.1 GPa8 Msi
148 GPa21.5 Msi

Bulk Modulus

62 GPa9 Msi
250 GPa36.3 Msi

Poisson's Ratio

0.23
0.27

Flexural Strength

11 MPa1.6 ksi
760 MPa110 ksi

Fracture Toughness (K_IC)

0.35 MPa·√m0.32 ksi·√in
2.2 MPa·√m2 ksi·√in

Hardness, Vickers

105 HV
2,000 HV

Hardness, Knoop

102 HK
2,000 HK

Hardness, Mohs

3.3
9

Tensile Strength (Ultimate)

—
400 MPa58 ksi

Elongation at Break

—
0%

Compressive Strength

—
2,000 MPa290 ksi

Shear Strength

—
350 MPa50.8 ksi

Physical

Density and transition temperatures.

Density

2.64 g/cm³0.1 lb/in³
3.98 g/cm³0.14 lb/in³

Melting Point (Solidus)

848°C1,558 °F
2,053°C3,727 °F

Refractive Index

1.392
1.768

Light Transmission

92%
85%

Same in both: Porosity 0%

Thermal

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

Thermal Conductivity

11.3 W/m·K6.5 BTU/hr·ft·°F
27 W/m·K15.6 BTU/hr·ft·°F

Specific Heat Capacity

1,562 J/kg·K0.37 BTU/lb·°F
761 J/kg·K0.18 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

37 µm/m·K20.6 µin/in·°F
5.8 µm/m·K3.2 µin/in·°F

Max Service Temperature (continuous)

400°C752 °F
1,800°C3,272 °F

Min Service Temperature

-200°C-328 °F
-269°C-452 °F

Electrical

Conductivity and insulation.

Electrical Resistivity

1×10¹¹ Ω·m3.94×10¹⁸ µΩ·in
1×10¹⁴ Ω·m3.94×10²¹ µΩ·in

Dielectric Constant (1 MHz)

9
9.8

Volume Resistivity

1×10¹³ Ω·cm
1×10¹⁶ Ω·cm

Dielectric Strength

—
17 kV/mm432 V/mil

Dissipation Factor (1 MHz)

—
1×10⁻⁴

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

35 / 100
95 / 100

Manufacturability

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

Machinability

25 / 100
5 / 100

Polishability

60 / 100
98 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

250 MJ/kg107,481 BTU/lb
400 MJ/kg171,969 BTU/lb

Embodied Carbon (primary production)

18 kg CO₂/kg
60 kg CO₂/kg

Typical Recycled Content

0%
5%

Embodied Water

—
250 L/kg30 gal/lb

Common Calculations

Ratios derived from the values above.

Specific Stiffness (E / density)

24.6 MN·m/kg
100.5 MN·m/kg

Thermal Diffusivity

2.7 mm²/s
8.9 mm²/s

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 scaleSapphire

Manufacturing and finishing

CapabilityLiFSapphire
Default condition—Annealed Glass
Relative cost$$$$ High$$ Standard
Min. machined wall——
Best machined surface——

LiF vs Sapphire — frequently asked

What is the difference between LiF and Sapphire?

LiF and Sapphire are both glass grades. Sapphire is harder — 2,000 HV against 105 HV for LiF — which matters for wear surfaces and threads. LiF is lighter (2.64 g/cm³ vs 3.98 g/cm³ for Sapphire) and Sapphire is stiffer (400 GPa vs 64.8 GPa).

Which is cheaper, LiF or Sapphire?

Sapphire is the lower-cost material: it sits in the standard tier ($$) while LiF is high ($$$$). 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, LiF or Sapphire?

LiF. Its machinability rates poor (25/100) against not recommended (5/100) for Sapphire.

Ready to make it?

Upload a CAD file and FabDigit prices the part in LiF and Sapphire 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.