Coltan

Coltan is columbite—tantalite, the ore from which niobium and tantalum are extracted, and it occupies the single inversion in this taxonomy: the ore outranks its metals. Refined niobium and tantalum fall to industrial metals, while the ore holds a category of its own. That is deliberate, and the reason is that coltan is what actually trades. It is what gets smuggled, what gets fought over, and what gets named in legislation. Nobody fights over tantalum. They fight over sacks of ore.

The physical reason sits behind everything else in the category. Coltan can be dug with a shovel and carries high value per kilogram, so a quantity worth having is a quantity a person can carry. A mineral that requires no capital to extract and no bulk transport to move is a mineral that can finance an armed group, and almost nothing else on this list combines those two properties — which is the same structural point that explains artisanal cobalt in the same country, arrived at from the opposite direction.

The date is c. 1950, on tantalum capacitors, with the Congo boom from 2000. The price spike of 2000—01 is popularly attributed to the launch of a games console; that is a simplification which credits one product for a general shortage in capacitors and telecommunications components, compounded by speculation, and it is worth not repeating.

Its regulatory history is unusually instructive because the instrument did not do what it was meant to. Section 1502 of the Dodd-Frank Act of 2010 made coltan one of four conflict minerals, with tin, tungsten and gold, and required companies registered with the Securities and Exchange Commission to report on sourcing from the Democratic Republic of the Congo and its neighbours. Rather than trace, buyers withdrew.

Laura Seay's account for the Center for Global Development, written in January 2012 before the rule was even implemented, sets out the sequence. Kabila banned mining in the Kivus and Maniema in September 2010, lifting it in March 2011. As the deadline approached, the Malaysia Smelting Corporation — which had been buying up to eighty percent of eastern Congolese tin — stopped, because it could not guarantee that its material would be tagged as conflict-free. North Kivu tin exports reportedly fell ninety percent, and only three of Goma's twenty-five exporters remained active. Local civil society estimated that one to two million people in the mining sector lost work, which with dependents reaches five to twelve million, though Seay notes those figures are hard to verify. Violence in the Kivus did not decline. Smuggling rose, and armed groups moved to timber, cannabis and palm oil. A disclosure rule intended to clean a supply chain produced a de facto embargo instead.

The current position shows why the structure has outlasted every attempt on it. M23 seized the Rubaya coltan mine in North Kivu on 30 April 2024. Rubaya supplies roughly fifteen percent of world coltan, mined largely by hand, and United Nations estimates put the group's revenue at at least $800,000 a month from taxing some 120 tonnes passing through monthly — traders paying $4 a kilogram to M23 and a further $3 a kilogram to the Rwandan government once the material crosses the border. The Washington Accords between the DRC and Rwanda were finalized on 4 December 2025 and accompanied the same day by a United States—DRC strategic partnership on critical minerals, framed as reducing Congo's exposure to Chinese dominance of mineral supply. In February 2026 Kinshasa added the rebel-held Rubaya mine to a shortlist of strategic assets offered to the United States, which is to say it offered a buyer an asset it did not control. Sanctions followed through 2026 on the Rwanda Defence Force and senior officers, on former president Kabila, and on FDLR and M23 commanders.

Fourteen years separate the disclosure regime from the capture of Rubaya, and the sequence is the category's argument: a traceability rule that removed demand instead of cleaning it, followed by a minerals partnership that supplies demand without controlling the ground. Coltan is the clearest case on this list of a commodity where every instrument attempted has acted on the buyer, because no one has been able to act on the mine. On boundaries: columbite—tantalite ore and concentrate are here. Refined niobium and tantalum are industrial metals — the one place in this taxonomy where an ore and its metals sit in different categories, and intentionally so. Tantalum capacitors are electrical equipment, with this category alongside where an entry turns on sourcing. Niobium alloyed into steel follows the alloy rule to iron and steel. Tin, tungsten and gold keep their own categories, and an entry about the conflict-minerals regime as a regime carries all four. The date is c. 1950, on tantalum capacitors, with the Congo boom from 2000.