Wollastonite
Wollastonite is a calcium metasilicate (CaSiO₃) mineral used both as a ceramic body constituent and as a functional filler, supplied in acicular, milled, surface-treated, calcined and ceramic grades.
Reference datasheet — Wollastonite 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 ACIC condition
Wollastonite tempers and conditions
Wollastonite is supplied in 4 conditions, soft to hard. ACIC is the default FabDigit quotes; the values on this page are for it.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ACICDefault Acicular high-aspect-ratio powder | Default general-purpose grade: needle-like particles (aspect ratio ~15:1–20:1) for reinforcing ceramics, plastics, coatings and friction materials. | 350 | 0.1 | 380 HV | 3 W/m·K | |
Solution annealed | Choose for polymer compounds (PA, PP, PBT, phenolic) where coupling agent is needed for strength, impact and low moisture pickup. | 350 | 0.3 | 380 HV | 2 W/m·K | |
Finely milled blocky powder | Pick when low viscosity, high loading and smooth surface finish matter more than reinforcement (paints, sanitaryware bodies, glazes, adhesives). | 0.1 | 380 HV | 3 W/m·K | ||
Calcined / high-brightness ceramic grade | Use for wall tile, sanitaryware and low-loss electrical ceramic bodies needing minimum LOI, low iron and high whiteness for fast firing. | 0.1 | 400 HV | 3 W/m·K |
Supply forms, finishes and certifications
Ways Wollastonite is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
CER | Fired wollastonite ceramic body | Supply option |
What is Wollastonite?
Wollastonite is a calcium metasilicate (CaSiO₃) mineral used both as a ceramic body constituent and as a functional filler, supplied in acicular, milled, surface-treated, calcined and ceramic grades. Engineers select it for low firing shrinkage, acicular reinforcement and low loss on ignition, with a density of 2.87 g/cm³ and use up to about 1000 °C. In ceramic bodies it is dry-pressed, extruded or slip-cast; in polymers and coatings it is melt-compounded or dispersed as a reinforcing filler. It is not a structural monolithic ceramic and is not weldable, so parts are joined with frits, glazes or adhesives; talc or milled silica fillers are the usual alternatives. Wollastonite has a density of 2.87 g/cm³ (0.104 lb/in³), lighter than 77% of ceramic grades. It melts at 1,540°C (2,804 °F). Wollastonite has a tensile strength of 350 MPa (50.8 ksi), stronger than 71% of ceramic grades. Elongation at break is 0.1% and the elastic modulus is 110 GPa (16 Msi).
What is Wollastonite used for?
- low-shrinkage tile bodies
- ceramic glaze fluxing agent
- friction material filler
- reinforcing filler in composites
Advantages
- Low embodied carbon — 0.12 kg CO₂/kg, better than 100% of ceramic grades
- Easy to machine — 45/100, better than 86% of ceramic grades
- Lightweight — 2.87 g/cm³ (0.104 lb/in³), better than 77% of ceramic grades
Limitations
- Needs corrosion protection — 40/100, worse than 96% of ceramic grades
- Poor heat conductor — 2.5 W/m·K (1.44 BTU/hr·ft·°F), worse than 83% of ceramic grades
Wollastonite properties
Typical room-temperature values for Wollastonite-ACIC; bars are the position among ceramic grades.
Physical3
Wollastonite has a density of 2.87 g/cm³ (0.104 lb/in³), lighter than 77% of ceramic grades. It melts at 1,540°C (2,804 °F).
Mechanical12
Wollastonite has a tensile strength of 350 MPa (50.8 ksi), stronger than 71% of ceramic grades. Elongation at break is 0.1% and the elastic modulus is 110 GPa (16 Msi).
Thermal5
Wollastonite is rated for continuous service to 1,000°C (1,832 °F). It conducts heat at 2.5 W/m·K (1.44 BTU/hr·ft·°F), worse than 83% of ceramic grades. Thermal expansion is 6.5 µm/m·K (3.61 µin/in·°F).
Electrical4
Wollastonite has an electrical resistivity of 1×10¹¹ Ω·m.
Chemical & Environmental2
Corrosion resistance is fair (40/100), worse than 96% of ceramic grades.
Sustainability4
Producing a kilogram of Wollastonite takes about 2 MJ of energy and emits 0.12 kg of CO₂ — less than 100% of ceramic grades. Typical recycled content is 0%.
Manufacturability1
Wollastonite's machinability is fair (45/100, better than 86% of ceramic grades).
Common Calculations4
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the ceramic family
Yield strength against density for every ceramic grade FabDigit runs. Wollastonite is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Wollastonite
Is Wollastonite easy to machine?
Fired wollastonite bodies are green-machinable before firing and require diamond tooling after firing; the powder itself is only mildly abrasive (Mohs 4.5), so it is gentle on compounding screws and paint mills compared with silica or alumina fillers.
Can Wollastonite be welded?
Not weldable; ceramic parts are joined by glass-frit sealing, glaze bonding or inorganic/epoxy adhesives.
Can Wollastonite be formed, bent or molded?
Dry-pressed, extruded or slip-cast in ceramic bodies where its low LOI and acicular habit give fast firing and very low shrinkage; as a filler it is melt-compounded at 15–40 wt % into thermoplastics or dispersed in coatings and friction resins.
Wollastonite 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 |
|---|---|---|
| SiO2theoretical CaSiO3 = 51.7 % SiO2 | 48 – 52.5 | 51.7 |
| Fe2O3lower in high-brightness ceramic grades | 0.05 – 0.9 | 0.35 |
| Al2O3 | 0.1 – 1.2 | 0.45 |
| MgOfrom diopside/calcite accessories | 0.1 – 1.5 | 0.5 |
| MnO | 0 – 0.2 | 0.05 |
| TiO2 | 0 – 0.1 | 0.03 |
| K2O+Na2O | 0 – 0.5 | 0.15 |
| LOI<0.5 % for calcined grades | 0.2 – 3 | 1 |
| CaOtheoretical 48.3 % | ≥ 43 (balance) |
What surface finishes work on Wollastonite?
Fired bodies accept conventional glazes and can be lapped/polished to a semi-gloss; in polymers the acicular grade slightly reduces surface gloss unless silane-treated fine grades are used.
Equivalent designations
Standards and trade names that resolve to Wollastonite in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Also called
- CaSiO3
How much does Wollastonite cost?
Wollastonite is a budget-cost ceramic ($), cheaper than about 90% 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.
Wollastonite — frequently asked
What is Wollastonite used for?
Wollastonite is typically used for low-shrinkage tile bodies, ceramic glaze fluxing agent, friction material filler and reinforcing filler in composites. In short: very low firing shrinkage; acicular reinforcing filler; low-abrasion mineral filler.
What is the tensile strength of Wollastonite?
Wollastonite has a typical tensile strength of 350 MPa (50.8 ksi) — stronger than 71% of ceramic grades. Strength varies by condition: see the 4 listed tempers.
Is Wollastonite easy to machine?
Reasonably — machinability is rated fair (45/100, better than 86% of ceramic grades). Fired wollastonite bodies are green-machinable before firing and require diamond tooling after firing; the powder itself is only mildly abrasive (Mohs 4.5), so it is gentle on compounding screws and paint mills compared with silica or alumina fillers.
Can Wollastonite be welded?
Not weldable; ceramic parts are joined by glass-frit sealing, glaze bonding or inorganic/epoxy adhesives.
What surface finishes work on Wollastonite?
Fired bodies accept conventional glazes and can be lapped/polished to a semi-gloss; in polymers the acicular grade slightly reduces surface gloss unless silane-treated fine grades are used.
Can Wollastonite be formed, bent or molded?
Dry-pressed, extruded or slip-cast in ceramic bodies where its low LOI and acicular habit give fast firing and very low shrinkage; as a filler it is melt-compounded at 15–40 wt % into thermoplastics or dispersed in coatings and friction resins.
What is the maximum service temperature of Wollastonite?
Wollastonite is rated for continuous use to about 1,000°C (1,832 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does Wollastonite cost?
Wollastonite is a budget-cost ceramic ($), cheaper than about 90% 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
- Industrial Minerals & Rocks — Wollastonite chapter — SME (2006)
- Handbook of Fillers, 4th ed. — ChemTec Publishing (2016)
- Wollastonite functional filler grades (acicular / surface-treated) — Imerys / NYCO Minerals (2023)
- Mineral Commodity Summaries — Wollastonite — USGS (2024)
- GB/T (wollastonite powder for ceramics and fillers) product specifications (2020)
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.