Wollastonite: Characteristics
Needle crystals and gas-free calcium: the two tricks that matter
What this tab covers The supply and physical characteristics of the commodity. Supply: current production, inventories and stocks, capacity utilisation, geographic and producer concentration, how fast supply responds to price, the project pipeline and capital spending, and logistics and export flows. Material: the physical and chemical properties that set its grade, price and end uses (for example purity and conductivity for metals, API gravity, sulfur and energy content for fuels, moisture, protein and fibre quality for crops).Supply volume characteristics
| Characteristic | Figure | What it means | Source |
|---|---|---|---|
| Current production volume | about 860,000 t (2025e), excluding withheld US output | China mined about 600,000 t, India 120,000 t, Mexico 100,000 t and Canada 30,000 t. US output from two New York miners is withheld but rose 14% in 2025. | USGS MCS 2026, Wollastonite |
| Inventory and stock levels | not published | There are no exchange or government stocks (US Government Stockpile: none). Stocks are held as milled product by producers and compounders. | USGS MCS 2026 |
| Capacity utilisation | not published | India's 108,383 t in 2021-22 came from three Rajasthan mines, almost all from Udaipur district. Mill capacity for fine acicular grades, not mining, is the usual bottleneck. | IBM Indian Minerals Yearbook 2022 |
| Geographic and producer concentration | China about 70%; top-3 (China, India, Mexico) about 95%; HHI about 5,200 | Highly concentrated by country. Company shares are not published; Wolkem in India supplies about 13% of the reported world total, and NYCO and Vanderbilt are the US producers. | USGS MCS 2026 (HHI computed, US excluded); IBM 2022 |
| Supply elasticity | moderate: mining is simple but grade qualification takes time | World resources exceed 100 Mt, but each plastics or friction customer qualifies a specific grade, so switching supplier is slow. Output dipped in 2020 and recovered. | USGS MCS 2026 |
| Project pipeline and CapEx | not published | No named projects with capacity are reported. Demand upside comes from the 2024 US ban on chrysotile asbestos, which could move brake and friction makers to wollastonite. India's reserves are 2.68 Mt (IBM 2020), about 22 years at current output. | USGS MCS 2026; IBM 2020 |
| Logistics and export flows | modest trade in bagged milled grades; India exported 11,705 t and imported 30,625 t in 2021-22 | Belgium took 57% of India's exports, while 99% of India's imports came from China. The US was a net exporter in 2025. Trade is hidden in generic tariff codes, so world figures are not published. | IBM 2022; USGS MCS 2026 |
Material characteristics Industrial mineral
Wollastonite is natural calcium silicate. Two features drive its value: it brings calcium into ceramics without releasing CO2 or gas on firing, and it forms needle-shaped (acicular) crystals that reinforce plastics, paints and brake pads. Fine, bright, high aspect ratio and surface-treated grades sell at many times the price of coarse ceramic powder.
| Property | Value / specification | Why it matters | Source |
|---|---|---|---|
| Chemistry | CaSiO3: theoretical 48.3% CaO, 51.7% SiO2; commercial grades low in iron | Supplies CaO to tile bodies and glazes with near-zero loss on ignition, allowing fast firing | stoichiometry; USGS MCS 2026 |
| Aspect ratio | high aspect ratio grades roughly 15:1 to 20:1; powder grades about 3:1 to 5:1 (indicative) | Needles stiffen plastics and friction products; this sets most of the price premium | USGS MCS 2026 (premium); ratios indicative |
| Particle size | from coarse ceramic grades to fine micronised powders of a few microns (indicative) | Finer grades disperse in paints and polymers and sell for more | USGS MCS 2026 |
| Brightness / whiteness | high-brightness concentrate after removal of garnet and diopside | White fillers are needed in paints, plastics and white tiles | USGS MCS 2026 |
| Surface treatment | silane or other coatings on some grades | Bonds the mineral to the polymer, raising strength and price | USGS MCS 2026 |
| Hardness and melting point | Mohs about 4.5-5; melts at about 1,540 C (indicative) | Heat stability suits it to welding fluxes, casting powders and asbestos replacement | mineralogy reference values, indicative |