Wollastonite
A needle-shaped calcium silicate that strengthens ceramics, plastics and paint, and replaced asbestos in brakes and boards.
Industrial minerals · No. 72
- Not on a critical list
A white rock that grows as tiny needles quietly took over the brake pads and boards where asbestos used to be.
Chart: Illustration: Wollastonite
Where it comes from
Chart: Map of where it comes from
It forms where silica-rich limestone is cooked by deep heat or hot fluids near magma, then is dug from open pits. World output was about 860,000 t in 2025.
Three things to know
- China mined about 600,000 t in 2025, roughly 70% of the reported world total, with India and Mexico far behind.
- Its needle-shaped crystals stiffen plastics, paint and brake pads, and fine high-aspect grades sell for many times coarse ceramic powder.
- The 2024 US ban on chrysotile asbestos could push more wollastonite into brake and friction products.
The journey
- 1 Baked limestoneSilica-rich limestone altered by heat or fluids
- 2 Open pitOre dug from shallow pits
- 3 CleaningGarnet and diopside removed magnetically
- 4 GrindingMilled to powder or needle grades
- 5 CoatingSurface treated for use in plastics
- 6 ProductsCeramics, plastics, paint and brake linings