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Quartzite vs Soapstone

Natural Material · grade comparison

Quartzite and Soapstone are both natural material grades. Quartzite is the stronger of the two: tensile strength 17 MPa (2.47 ksi) against 10 MPa (1.45 ksi) for Soapstone, about 70% more. Quartzite is lighter (2.65 g/cm³ vs 2.95 g/cm³ for Soapstone) and Quartzite is stiffer (75 GPa vs 60 GPa). On the shop floor, Soapstone machines more easily (excellent vs not recommended).

QuartziteChoose it when strength drives the design, or when weight is the constraint.

SoapstoneChoose it when the part sees heat, or when the part is machined in volume.

Quartzite vs Soapstone: properties

QuartziteSoapstone

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

75 GPa10.9 Msi
60 GPa8.7 Msi

Shear Modulus

29 GPa4.2 Msi
20 GPa2.9 Msi

Bulk Modulus

40 GPa5.8 Msi
36 GPa5.2 Msi

Poisson's Ratio

0.17
0.27

Tensile Strength (Ultimate)

17 MPa2.5 ksi
10 MPa1.5 ksi

Compressive Strength

250 MPa36.3 ksi
85 MPa12.3 ksi

Flexural Strength

28 MPa4.1 ksi
18 MPa2.6 ksi

Shear Strength

34 MPa4.9 ksi
18 MPa2.6 ksi

Fracture Toughness (K_IC)

1.1 MPa·√m1 ksi·√in
1 MPa·√m0.91 ksi·√in

Hardness, Knoop

770 HK
60 HK

Hardness, Mohs

7
3

Physical

Density and transition temperatures.

Density

2.65 g/cm³0.1 lb/in³
2.95 g/cm³0.11 lb/in³

Melting Point (Solidus)

1,670°C3,038 °F
1,500°C2,732 °F

Porosity

0.4%
0.6%

Thermal

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

Specific Heat Capacity

780 J/kg·K0.19 BTU/lb·°F
980 J/kg·K0.23 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

11 µm/m·K6.1 µin/in·°F
9 µm/m·K5 µin/in·°F

Max Service Temperature (continuous)

400°C752 °F
900°C1,652 °F

Same in both: Thermal Conductivity 6 W/m·K3.5 BTU/hr·ft·°F · Min Service Temperature -60°C-76 °F

Electrical

Conductivity and insulation.

Electrical Resistivity

1,000,000 Ω·m3.94×10¹³ µΩ·in
1×10⁸ Ω·m3.94×10¹⁵ µΩ·in

Dielectric Strength

—
6 kV/mm152 V/mil

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

93 / 100
92 / 100

Manufacturability

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

Machinability

7 / 100
90 / 100

Polishability

88 / 100
60 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

3 MJ/kg1,290 BTU/lb
2 MJ/kg860 BTU/lb

Embodied Carbon (primary production)

0.22 kg CO₂/kg
0.14 kg CO₂/kg

Embodied Water

25 L/kg3 gal/lb
20 L/kg2.4 gal/lb

Same in both: Typical Recycled Content 0%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

6 kN·m/kg
3 kN·m/kg

Specific Stiffness (E / density)

28.3 MN·m/kg
20.3 MN·m/kg

Thermal Diffusivity

2.9 mm²/s
2.1 mm²/s

Same in both: 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

CapabilityQuartziteSoapstone
Default condition——
Relative cost$$ Standard$$ Standard
Min. machined wall——
Best machined surface——

Quartzite vs Soapstone — frequently asked

Is Quartzite stronger than Soapstone?

Yes. Quartzite has a typical tensile strength of 17 MPa (2.47 ksi) against 10 MPa (1.45 ksi) for Soapstone — about 70% more.

Which is cheaper, Quartzite or Soapstone?

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

Which is easier to machine, Quartzite or Soapstone?

Soapstone. Its machinability rates excellent (90/100) against not recommended (7/100) for Quartzite.

Ready to make it?

Upload a CAD file and FabDigit prices the part in Quartzite and Soapstone 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.