Steatite vs Synthetic Sapphire
Ceramic · grade comparison
Steatite and Synthetic Sapphire are both ceramic grades. Synthetic Sapphire is the stronger of the two: tensile strength 400 MPa (58 ksi) against 60 MPa (8.7 ksi) for Steatite, about 6.7 times as much. Synthetic Sapphire is harder — 2,000 HV against 650 HV for Steatite — which matters for wear surfaces and threads. Steatite is lighter (2.8 g/cm³ vs 3.98 g/cm³ for Synthetic Sapphire) and Synthetic Sapphire is stiffer (400 GPa vs 100 GPa).
SteatiteChoose it when weight is the constraint.
Synthetic SapphireChoose it when strength drives the design, or when surface hardness matters.
Steatite vs Synthetic Sapphire: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all ceramic 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 ceramic 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
Tensile Strength (Ultimate)
Elongation at Break
Compressive Strength
Flexural Strength
Fracture Toughness (K_IC)
Hardness, Vickers
Hardness, Knoop
Hardness, Mohs
Shear Strength
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)
Min Service Temperature
Electrical
Conductivity and insulation.
Electrical Resistivity
Dielectric Strength
Dielectric Constant (1 MHz)
Dissipation Factor (1 MHz)
Volume Resistivity
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
Sintering / Firing Temperature
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Typical Recycled Content
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 ceramic grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
Manufacturing and finishing
| Capability | Steatite | Synthetic Sapphire |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$$$ High | $$$$ High |
| Min. machined wall | — | — |
| Best machined surface | — | — |
Steatite vs Synthetic Sapphire — frequently asked
Is Synthetic Sapphire stronger than Steatite?
Yes. Synthetic Sapphire has a typical tensile strength of 400 MPa (58 ksi) against 60 MPa (8.7 ksi) for Steatite — about 6.7 times as much.
Which is cheaper, Steatite or Synthetic Sapphire?
Both sit in the same relative cost tier ($$$$, high); the part price will be decided by machining time, tolerance and quantity rather than by the material.
When should I choose Steatite over Synthetic Sapphire?
Pick Steatite when weight is the constraint. Pick Synthetic Sapphire when strength drives the design, or when surface hardness matters.
Ready to make it?
Upload a CAD file and FabDigit prices the part in Steatite and Synthetic 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.