CVD Diamond (Optical) vs Sapphire
Glass · grade comparison
CVD Diamond (Optical) and Sapphire are both glass grades. CVD Diamond (Optical) is lighter (3.51 g/cm³ vs 3.98 g/cm³ for Sapphire) and CVD Diamond (Optical) is stiffer (1,140 GPa vs 400 GPa). On the shop floor, Sapphire sits in a lower cost tier (standard, $$) than CVD Diamond (Optical) (high, $$$$).
CVD Diamond (Optical)Choose it when weight is the constraint.
SapphireChoose it when the part sees heat, or when cost is the deciding factor.
CVD Diamond (Optical) vs Sapphire: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all glass grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all glass grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
Shear Modulus
Bulk Modulus
Poisson's Ratio
Compressive Strength
Flexural Strength
Fracture Toughness (K_IC)
Hardness, Knoop
Hardness, Mohs
Elongation at Break
Shear Strength
Hardness, Vickers
Same in both: Tensile Strength (Ultimate) 400 MPa58 ksi
Physical
Density and transition temperatures.
Density
Melting Point (Solidus)
Refractive Index
Light Transmission
Same in both: Porosity 0%
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Same in both: Min Service Temperature -269°C-452 °F
Electrical
Conductivity and insulation.
Electrical Resistivity
Dielectric Constant (1 MHz)
Volume Resistivity
Dielectric Strength
Same in both: Dissipation Factor (1 MHz) 1×10⁻⁴
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Polishability
Sustainability
Primary-production footprint per kilogram.
Typical Recycled Content
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Thermal Diffusivity
Thermal Shock Resistance Index
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.
Manufacturing and finishing
| Capability | CVD Diamond (Optical) | Sapphire |
|---|---|---|
| Default condition | — | Annealed Glass |
| Relative cost | $$$$ High | $$ Standard |
| Min. machined wall | — | — |
| Best machined surface | — | — |
CVD Diamond (Optical) vs Sapphire — frequently asked
What is the difference between CVD Diamond (Optical) and Sapphire?
CVD Diamond (Optical) and Sapphire are both glass grades. CVD Diamond (Optical) is lighter (3.51 g/cm³ vs 3.98 g/cm³ for Sapphire) and CVD Diamond (Optical) is stiffer (1,140 GPa vs 400 GPa). On the shop floor, Sapphire sits in a lower cost tier (standard, $$) than CVD Diamond (Optical) (high, $$$$).
Which is cheaper, CVD Diamond (Optical) or Sapphire?
Sapphire is the lower-cost material: it sits in the standard tier ($$) while CVD Diamond (Optical) is high ($$$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.
When should I choose CVD Diamond (Optical) over Sapphire?
Pick CVD Diamond (Optical) when weight is the constraint. Pick Sapphire when the part sees heat, or when cost is the deciding factor.
Ready to make it?
Upload a CAD file and FabDigit prices the part in CVD Diamond (Optical) 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.