Indium is the classic refinery-only byproduct: there are no indium mines. Every tonne of indium reaches market as a trace co-product from zinc smelting, primarily from sphalerite ores. USGS MCS 2025 places world 2024 refinery production at 1,080 tonnes (estimated), with China at 70% (760 t), Korea at ~17% (180 t), and Japan at ~6% (60 t). The US has had zero refinery production throughout 2020–2024 and imports all its supply.

The dominant end use — ITO for flat-panel displays and touchscreens — drives most demand. Emerging growth comes from indium phosphide (InP) substrates in 5G fiber-optic networks and AI-specialized photonic chips; USGS notes a domestic InP substrate company reported 67% year-on-year revenue growth in Q2 2024. Data-center expansion adds further incremental demand through ITO-coated fibers and indium-based solders.

The September 2024 Section 301 tariff extension to critical minerals (25% ad valorem on Chinese indium) is geopolitically salient: China accounts for 70% of world refinery production and had become 25% of US imports by the time of the announcement, up from an 8% four-year average. US warehouse prices rose 42% in 2024 (from $244/kg to $340/kg), peaking at $420/kg in June.

Reserves are not independently published for indium; USGS MCS 2025 explicitly refers users to the zinc chapter. The indium content of zinc deposits ranges from <1 ppm to 100 ppm, making economically recoverable quantities highly mine-specific. Supply cannot respond independently to indium price signals because production volumes are governed by zinc output at the smelter level.

The substitution threat to ITO — carbon nanotubes, PEDOT, silver nanowires, graphene, zinc oxide nanopowder, antimony tin oxide — has been discussed for over a decade without displacing ITO at commercial scale, partly because large-scale recycling of ITO scrap (primarily in Japan and Korea) already moderates effective supply tightness.