Material Insights · Understanding the Material World

Thallium: Characteristics

Soft, dense, toxic and still hard to replace

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

CharacteristicFigureWhat it meansSource
Current production volumeabout 10 t (10,000 kg) world refinery output (2023, latest)Thallium is recovered only as a by-product from flue dust of copper, lead and zinc ore roasting. China, Kazakhstan and Russia lead; most producers withhold data. US price $9,300/kg in 2025.USGS MCS 2026, Thallium
Inventory and stock levelsnot publishedUSGS reports that data on inventory for domestic use remained unavailable. There is no exchange and no government stockpile. Unrecovered thallium sits in smelter dusts and residues.USGS MCS 2026
Capacity utilisationnot publishedRecovery depends on whether smelters run thallium circuits on their flue dust. Most thallium in base-metal ores is not recovered, so potential capacity far exceeds output, but no figure exists.USGS MCS 2026
Geographic and producer concentrationChina, Kazakhstan and Russia lead; HHI not computable (country data withheld)Thallium-rich deposits are known in Brazil, China, North Macedonia and Russia. US import sources 2021-24: Mexico 90%, France 4%, Japan 4%, Israel 2%.USGS MCS 2026
Supply elasticityvery low: output set by zinc and lead smelting, not thallium priceThallium is a by-product with a companionality of about 95% (share of output from host metals). A thallium price rise can only prompt more recovery from existing smelter dusts.USGS MCS 2026; criticality brief (companionality 95, host zinc and copper)
Project pipeline and CapExnone announcedNo new thallium recovery projects are reported. Research on volcano-related U-Mo-Tl mineralisation in northeastern China points to possible new resources.USGS MCS 2026
Logistics and export flowstiny, tightly controlled flows; US exports of thallium articles 2,800 kg (2025)Thallium moves as metal granules, compounds or in devices. As a highly toxic material it ships under hazardous-goods rules. US unwrought metal trade was nil in 2025.USGS MCS 2026

Material characteristics Metal / hard commodity

Thallium is a soft, dense, highly toxic heavy metal. It is used in tiny amounts where its optical and nuclear properties are hard to replace: thallium-doped sodium iodide gamma detectors, infrared optics, high-temperature superconductors, high-density liquids and the cardiac imaging isotope thallium-201. Purity and toxicity control dominate commercial handling.

PropertyValue / specificationWhy it mattersSource
Purity / grade99.99% granules (price basis, 100 g lots)Reference grade for the $9,300/kg (2025) priceUSGS MCS 2026
Toxicity limitUS EPA drinking-water maximum contaminant level 2 parts per billionDrives strict handling, packaging and disposal costsUSGS MCS 2026 citing US EPA
Density and melting pointabout 11.85 g/cm3; melts about 304 °C (indicative, handbook values)High density for heavy liquids and glass; low melting point for alloys and low-temperature thermometers with mercuryCRC Handbook (indicative)
Crustal abundanceabout 0.7 ppmAbundant but dispersed; only sulphide ores give recoverable thalliumUSGS MCS 2026
Scintillation activatorNaI(Tl): thallium-doped sodium iodide crystalsIndustry standard gamma-ray detector; substitutes are less cost effectiveUSGS MCS 2026
Medical isotopeTl-201, half-life about 73 hours (indicative)Cardiac stress imaging; being displaced by technetium-99mUSGS MCS 2026; nuclear data (indicative)