Kyanite: Characteristics
Why kyanite must be pre-fired but andalusite need not
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 | no world total: South Africa andalusite 120,000 t, US kyanite 80,000 t, France andalusite 60,000 t, China andalusite crude ore 50,000 t, Peru 40,000 t (2025e) | USGS does not add these up because countries report different minerals on different bases. India produced 2,500 t of kyanite and sillimanite. | USGS MCS 2026, Kyanite and Related Minerals |
| Inventory and stock levels | not published | There are no exchange or government stocks. Refractory makers carry raw-material stocks as cover against South African supply disruption. | USGS MCS 2026 |
| Capacity utilisation | Kyanite Mining Corp about 60-65% of concentrate capacity (derived) | KMC has about 130,000 t a year of concentrate capacity and 39,000 t of calcining capacity. It produced 86,000 t of kyanite plus mullite in 2022 and the US 80,000 t in 2025. South African andalusite has run below potential because of power cuts, floods, labour disputes and shipping problems. | Virginia Energy / SME Mining Engineering 2023; USGS MCS 2026 (ratio derived) |
| Geographic and producer concentration | South Africa about 34% of listed output; top-3 (South Africa, US, France) about 74%; HHI about 2,300 (indicative, mixes minerals) | Each country's output is dominated by one or two firms: Kyanite Mining Corp in the US, Imerys in France and South Africa, Andalucita S.A. in Peru. | USGS MCS 2026 (HHI computed); Virginia Energy 2023 |
| Supply elasticity | low: few mines; buyers substitute rather than wait for new supply | When andalusite is short, refractory makers switch to refractory bauxite or synthetic mullite, and vice versa. India's resources (9.1 Mt) are large, but beach-sand mining bans since 2013 (Tamil Nadu) and 2019 (private sector) cut sillimanite. | USGS MCS 2026 |
| Project pipeline and CapEx | not published; early-stage only | In April 2025 a heavy-mineral-sand project in Cameroon reported an inferred resource that includes kyanite. India approved mining of new mineral groups including andalusite. An Austrian refractory company bought a US refractory and minerals producer in January 2025. | USGS MCS 2026 |
| Logistics and export flows | US exported 37,000 t in 2025 at $510/t; India imports andalusite, 79% from South Africa | US imports came from South Africa (54%), Peru (24%) and France (18%) in 2021-24. South African exports fell in 2025 because of shipping problems. China exported under 7,000 t of andalusite. | USGS MCS 2026; IBM 2022 |
Material characteristics Industrial mineral
Kyanite, andalusite and sillimanite share the formula Al2SiO5 and become mullite when heated, which makes refractory bricks and castables that hold their shape above 1,500 C. Buyers judge alumina content, iron and alkali impurities, grain size and how much the grain expands on firing. Kyanite expands strongly, so it is usually calcined first; andalusite expands little and is used raw.
| Property | Value / specification | Why it matters | Source |
|---|---|---|---|
| Alumina content | theoretical 62.9% Al2O3, 37.1% SiO2; calcined mullite grades above 55% Al2O3 | Higher alumina means higher refractoriness and price | stoichiometry; Virginia Energy 2023 |
| Iron oxide | mullite grades under 0.85% Fe2O3 | Iron and alkalis form low-melting phases that weaken refractories at heat | Virginia Energy / SME 2023 |
| Expansion on firing | kyanite expands much more than andalusite on conversion to mullite (indicative: kyanite about 16-18% by volume, andalusite a few%) | Decides whether the mineral is calcined first or used raw, and how it offsets shrinkage in castables | refractory literature, indicative |
| Grain size | sold as graded mesh sizes of concentrate and calcined grain | Refractory recipes need specific sizes for packing | Virginia Energy 2023 |
| Ore grade | Virginia ore 10-40% kyanite, average about 25% | Low grade means much rock is moved per tonne of concentrate | Virginia Energy 2023 |