Limestone vs Onyx
Natural Material · grade comparison
Limestone and Onyx are both natural material grades. Onyx is the stronger of the two: tensile strength 6 MPa (0.87 ksi) against 5 MPa (0.725 ksi) for Limestone, about 20% more. Limestone is lighter (2.4 g/cm³ vs 2.7 g/cm³ for Onyx) and Onyx is stiffer (50 GPa vs 30 GPa). On the shop floor, Limestone machines more easily (very good vs good) and Limestone sits in a lower cost tier (budget, $) than Onyx (standard, $$).
LimestoneChoose it when weight is the constraint, or when the part sees heat.
OnyxChoose it when strength drives the design.
Limestone vs Onyx: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all natural material 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 natural material 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, Mohs
Same in both: Shear Strength 10 MPa1.5 ksi · Hardness, Knoop 120 HK
Physical
Density and transition temperatures.
Density
Porosity
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
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.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Same in both: Typical Recycled Content 0%
Common Calculations
Ratios derived from the values above.
Specific Stiffness (E / density)
Thermal Diffusivity
Same in both: Specific Strength (UTS / density) 2 kN·m/kg · Thermal Shock Resistance Index 0
Strength versus weight
Yield strength against density for every natural material grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
Manufacturing and finishing
| Capability | Limestone | Onyx |
|---|---|---|
| Default condition | — | — |
| Relative cost | $ Budget | $$ Standard |
| Min. machined wall | — | — |
| Best machined surface | — | — |
Limestone vs Onyx — frequently asked
Is Onyx stronger than Limestone?
Yes. Onyx has a typical tensile strength of 6 MPa (0.87 ksi) against 5 MPa (0.725 ksi) for Limestone — about 20% more.
Which is cheaper, Limestone or Onyx?
Limestone is the lower-cost material: it sits in the budget tier ($) while Onyx is standard ($$). 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, Limestone or Onyx?
Limestone. Its machinability rates very good (80/100) against good (65/100) for Onyx.
Ready to make it?
Upload a CAD file and FabDigit prices the part in Limestone and Onyx 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.