Soapstone
Soapstone is a talc-rich metamorphic rock with a density of 2.95 g/cm³, offered in architectural, carving and stove grades.
Reference datasheet — Soapstone is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the ARCH condition
Soapstone tempers and conditions
Soapstone is supplied in 3 conditions, soft to hard. ARCH is the default FabDigit quotes; the values on this page are for it.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Carving / artistic grade | Pick for hand carving, sculpture blanks, welder's marking sticks and mould/pattern work where softness is the point. | 5 | 5 W/m·K | |||
ARCHDefault Architectural / countertop grade | Pick for countertops, sinks, sills and lab benches where scratch and edge durability matter more than carvability. | 10 | 6 W/m·K | |||
Heat-storage / refractory grade | Pick for masonry heaters, wood-stove liners and pizza/baking stones where high heat capacity and thermal-shock survival dominate. | 6 W/m·K |
What is Soapstone?
Soapstone is a talc-rich metamorphic rock with a density of 2.95 g/cm³, offered in architectural, carving and stove grades. It is selected for heat retention and chemical resistance — 6 W/m·K thermal conductivity, service to 900 °C and a corrosion resistance score of 92 — combined with the easiest fabrication in the stone family at a machinability score of 90, in slabs, sinks, tiles and carving blocks. The trade-off is softness and low strength: about 10 MPa in tension at a 60 GPa modulus, so it scratches in service and sections must stay thick. Granite is the alternative where surface hardness matters more than heat resistance. Soapstone has a density of 2.95 g/cm³ (0.107 lb/in³), heavier than 100% of natural material grades. It melts at 1,500°C (2,732 °F). Soapstone has a tensile strength of 10 MPa (1.45 ksi), weaker than 72% of natural material grades. The elastic modulus is 60 GPa (8.7 Msi).
What is Soapstone used for?
- Kitchen countertops and sinks
- Wood stove surrounds
- Laboratory bench tops
- Carving and sculpture
Advantages
- High service temperature — 900°C (1,652 °F), better than 100% of natural material grades
- Conducts heat well — 6 W/m·K (3.47 BTU/hr·ft·°F), better than 99% of natural material grades
- Good corrosion resistance — 92/100, better than 98% of natural material grades
- Stiff — 60 GPa (8.7 Msi), better than 94% of natural material grades
- Low embodied carbon — 0.14 kg CO₂/kg, better than 89% of natural material grades
Limitations
- Heavy — 2.95 g/cm³ (0.107 lb/in³), worse than 100% of natural material grades
Soapstone properties
Typical room-temperature values for Soapstone-ARCH; bars are the position among natural material grades.
Physical3
Soapstone has a density of 2.95 g/cm³ (0.107 lb/in³), heavier than 100% of natural material grades. It melts at 1,500°C (2,732 °F).
Mechanical11
Soapstone has a tensile strength of 10 MPa (1.45 ksi), weaker than 72% of natural material grades. The elastic modulus is 60 GPa (8.7 Msi).
Thermal5
Soapstone is rated for continuous service to 900°C (1,652 °F). It conducts heat at 6 W/m·K (3.47 BTU/hr·ft·°F), better than 99% of natural material grades. Thermal expansion is 9 µm/m·K (5 µin/in·°F).
Electrical2
Soapstone is an electrical insulator with a dielectric strength of 6 kV/mm (152.4 V/mil) and a resistivity of 1×10⁸ Ω·m.
Chemical & Environmental1
Corrosion resistance is excellent (92/100), better than 98% of natural material grades.
Sustainability4
Producing a kilogram of Soapstone takes about 2 MJ of energy and emits 0.14 kg of CO₂ — less than 90% of natural material grades. Typical recycled content is 0%.
Manufacturability2
Soapstone's machinability is excellent (90/100, better than 86% of natural material grades).
Common Calculations4
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Working with Soapstone
Is Soapstone easy to machine?
Cuts, drills and turns easily with carbide or even HSS/woodworking tools at high feed; use wet cutting or LEV because talc/amphibole dust is a respiratory hazard.
Can Soapstone be welded?
Not weldable; slabs are joined with epoxy or polyester stone adhesive, and colour-matched seams are hidden by wet-sanding the joint.
Can Soapstone be formed, bent or molded?
No plastic forming — shapes come from sawing, routing and hand rasping; edges are easily coved or bullnosed but stay thick (≥20 mm) to avoid breakage.
Soapstone chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| talc (Mg3Si4O10(OH)2)primary soft phase; higher in carving grades | 30 – 80 | 50 |
| chloriteadds toughness/hardness in architectural grades | 5 – 40 | 20 |
| magnesite / dolomite (carbonates)high in Finnish talc-magnesite stove stone | 0 – 40 | 15 |
| amphibole (tremolite/anthophyllite)asbestiform habit possible — dust control required | 0 – 15 | 5 |
| quartz | 0 – 5 | 1 |
| magnetite / iron oxides & sulfidessource of grey-green colour and veining | 0 – 8 | 3 |
| accessory minerals (serpentine, mica, ru | balance |
What surface finishes work on Soapstone?
Sand to 120–220 grit for a satin surface then oil or wax to darken the stone; scratches are simply sanded out in service, and no sealing is needed for chemical resistance.
How much does Soapstone cost?
Soapstone is a standard-cost natural material ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Soapstone — frequently asked
What is Soapstone used for?
Soapstone is typically used for kitchen countertops and sinks, wood stove surrounds, laboratory bench tops and carving and sculpture. In short: easiest-machining natural stone; highest stone service temperature; no sealer required.
What is the tensile strength of Soapstone?
Soapstone has a typical tensile strength of 10 MPa (1.45 ksi) — weaker than 72% of natural material grades. Strength varies by condition: see the 3 listed tempers.
Is Soapstone easy to machine?
Yes — machinability is rated excellent (90/100, better than 86% of natural material grades). Cuts, drills and turns easily with carbide or even HSS/woodworking tools at high feed; use wet cutting or LEV because talc/amphibole dust is a respiratory hazard.
Can Soapstone be welded?
Not weldable; slabs are joined with epoxy or polyester stone adhesive, and colour-matched seams are hidden by wet-sanding the joint.
What surface finishes work on Soapstone?
Sand to 120–220 grit for a satin surface then oil or wax to darken the stone; scratches are simply sanded out in service, and no sealing is needed for chemical resistance.
Can Soapstone be formed, bent or molded?
No plastic forming — shapes come from sawing, routing and hand rasping; edges are easily coved or bullnosed but stay thick (≥20 mm) to avoid breakage.
What is the maximum service temperature of Soapstone?
Soapstone is rated for continuous use to about 900°C (1,652 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does Soapstone cost?
Soapstone is a standard-cost natural material ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- Soapstone (vuolukivi) technical properties for heaters and interiors — Tulikivi Oyj (2022)
- Dimension Stone: properties and test methods (Stone Design Manual) — Marble Institute of America / NSI (2016)
- EN 1926 / EN 12372 / EN 1936 — natural stone compressive, flexural and density test methods — CEN (2018)
- Physical Properties of Rocks (thermal conductivity and heat capacity of talc schists) — Elsevier (2011)
- Mineral property data for talc, chlorite and magnesite — Mindat / Handbook of Mineralogy (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.